Jan. 5

Goal: students will be able to solve for F, t, impulse, p, v. Students will understand that seat belts and air bags help protect people by extending the time (and decreasing the force) if an accident occurs.

Impulse momentum notes

• Momentum
• Internal and External Forces

Internal Force – the forces between objects in a system.

External Forces – forces exerted from outside a system.

• It is important to define a system carefully to determine the status of the force.
• Inertia
• Recall that inertia is the tendency of an object to resist a change in its motion.
• Inertia is based upon mass
• Momentum and Impulse

• Momentum is a vector. The product of mass and velocity is momentum.
• Momentum is a quantity that is in the same direction as velocity.

Equation:  p = m v    Unit: kg*m/s

Momentum = mass * velocity

Momentum can be thought of as inertia in motion.

• Example
• A truck (m = 1700 kg) has a velocity of 4 m/s. A compact car (m = 900 kg) has a velocity of 10 m/s. Find the momentum of each.
• Impulse

The product of the net force and the time interval over which it acts.

Impulse is a vector quantity in the direction of the Force.

Equation: Impulse = F êt        Units: Newton-seconds

Example:  Car Crash

• Impulse-Momentum Theory

The equality of impulse and change in momentum is another way of writing Newton’s 2^nd Law.

Equation:  Fêt = êp

Force * change in time = change in momentum

• Example question
• A 500 g ball starts with a velocity of 10 m/s E. A bat hits the ball and is in contact with the ball for 0.1 sec. After being hit, the ball has a velocity of 10 m/s W. Find:
• The balls impulse
• Its change in momentum
• And the force the bat applied to the ball
• Angular Momentum

The product of an object’s mass, velocity, and distance from the center of rotation.

Ex. Hurricane’s have a large Angular momentum

• Conservation of Momentum

Law of Conservation of Momentum states that The Momentum of any isolated, closed system does not change.

The total momentum of an isolated system always remains constant.

The impulse-momentum theorem is another way of stating Newton’s 2nd law

• Conservation of Momentum

Equation:  p_a + p_b = p_a’ + p_b’

The momentum of 2 objects is equal to the momentum after a collision.

• Conservation of momentum Example problems
• A large box car (m = 2000 kg) heads east with a velocity of 2 m/s. It collides with a smaller box car (m=1500kg) at rest. The two box cars combine at impact. Find their velocity after impact.
• An object of mass M heads towards the E with a velocity of 4 m/s. An object of mass 4 M heads W with a velocity of 12 m/s. The two collide and combine at impact. Find their velocity after impact.
• Conservation of Momentum in 2 Dimensions

The total momentum of a system is the vector sum of the momenta of all parts of the system.

Example. Pool balls colliding at an angle and the direction they will go in.

• Find the impulse and the force acting on the egg.
• #1 You throw a 100 g egg at a fire blanket with a velocity of 10 m/s. It hits the blanket and comes to a complete stop in 0.8 seconds.
• #2 You throw a 100 g egg at a wall with a velocity of 10 m/s. It hits the wall and comes to a complete stop in 0.1 seconds.
• #3 compare and contrast your results.
•  

Momentum ws

Impulse momentum test-Jan. 30?

Jan. 6

Goal: students will be able to solve for F, t, impulse, p, v. Students will understand that seat belts and air bags help protect people by extending the time (and decreasing the force) if an accident occurs.

Impulse momentum example problems

Impulse momentum ws

Impulse momentum test-Jan. 28

Impulse momentum review ws

Jan. 9

Goal: students will be able to solve for F, t, impulse, p, v. Students will understand that seat belts and air bags help protect people by extending the time (and decreasing the force) if an accident occurs.

Students will understand that momentum is conserved (law of conservation of momentum)

Conservation of momentum example problems

1. A 1500 kg car traveling west at 30 m/s hits a 4500 kg truck traveling east with a velocity of 20 m/s. What is the velocity of the combined vehicles after impact?

2. A 3 kg ball with a velocity of 4 m/s and a 1 kg ball with a velocity of 2 m/s are thrown directly at each other. The balls collide and merge at impact. What is the velocity of the merged ball after impact?

3. A 50 kg projectile leaves a 240 kg launcher with a velocity of 350 m/s. What is the velocity of the launcher after the projectile has been fired?

The following are perfectly elastic collisions or are not perfectly inelastic collisions.

4. A 2 kg ball traveling west at 5 m/s collides head-on with a 1.60 kg ball traveling west at 9 m/s. After the collision, the 2 kg ball moves back with a velocity of 8 m/s (towards the east). Find the velocity of the 1.6 kg ball after the collision.

5. A 25 g marble moving towards the right with a velocity of 20 cm/s collides with a 10 g marble that is moving towards the right at 15 cm/s. After the collision, the 10 g marble moves to the right with a velocity of 22.1 cm/s. Find the velocity of the 25 g marble after the collision (answer in cm/s).

6. A 16 kg object moving towards the left (v = 12 m/s) hits a 4 kg object moving towards the right with a velocity of 6 m/s. After the collision, the 4 kg object has a velocity of 22.7 m/s towards the left. Find the velocity of the 16 kg object after the collision.

Conservation of momentum ws

Jan. 10

Goal: students will be able to solve for F, t, impulse, p, v. Students will understand that seat belts and air bags help protect people by extending the time (and decreasing the force) if an accident occurs.

Students will understand that momentum is conserved (law of conservation of momentum)

Review impulse momentum

Work on review ws

Impulse momentum test

Jan. 20

Jan. 11

Goal: students will be able to solve for F, t, impulse, p, v. Students will understand that seat belts and air bags help protect people by extending the time (and decreasing the force) if an accident occurs.

Students will understand that momentum is conserved (law of conservation of momentum)

Impulse momentum test-Jan. 20

Conservation of momentum ws-use as study guide for the quiz

Jan. 12

Goal: students will be able to solve for F, t, impulse, p, v. Students will understand that seat belts and air bags help protect people by extending the time (and decreasing the force) if an accident occurs.

Students will understand that momentum is conserved (law of conservation of momentum)

Impulse momentum waterballoon lab

Review ws

Jan. 13

Goal: students will be able to solve for F, t, impulse, p, v. Students will understand that seat belts and air bags help protect people by extending the time (and decreasing the force) if an accident occurs.

Students will understand that momentum is conserved (law of conservation of momentum)

CD -7-1-important concepts

Jan. 17

Goal: students will be able to solve for F, t, impulse, p, v. Students will understand that seat belts and air bags help protect people by extending the time (and decreasing the force) if an accident occurs.

Students will understand that momentum is conserved (law of conservation of momentum)

Lab-impulse momentum egg safety lab

Jan. 18

Goal: students will be able to solve for F, t, impulse, p, v. Students will understand that seat belts and air bags help protect people by extending the time (and decreasing the force) if an accident occurs.

Students will understand that momentum is conserved (law of conservation of momentum)

Collisions ws

Jan. 19

Goal: students will be able to solve for F, t, impulse, p, v. Students will understand that seat belts and air bags help protect people by extending the time (and decreasing the force) if an accident occurs.

Students will understand that momentum is conserved (law of conservation of momentum)

Impulse momentum kahoot

Jan. 20

Goal: students will be able to solve for F, t, impulse, p, v. Students will understand that seat belts and air bags help protect people by extending the time (and decreasing the force) if an accident occurs.

Students will understand that momentum is conserved (law of conservation of momentum)

Impulse momentum test

Jan. 23

Goal: be able to solve for W, P, t, F, d, KE, and PE

Goal: understand that energy is conserved although it can change forms

Goal: understand that work occurs when a force is applied to an object and it moves (not at right angles to each other)

Begin work, power, energy notes

5A: interpret evidence work energy theorem 5B: observe and describe examples of kinetic and potential energy and their transformations.

Students will be able to calculate kinetic and potential energy. 2.  Equations: 3.  Energy notes:

• Energy Forms

Kinetic Energy – energy that has motion

Potential Energy – stored energy because of its state or position.

• kinetic energy depends upon an object’s mass and velocity.
• Doing work on an object can increase the kinetic energy.

Formula:  KE= ½ m v²     Unit: joules

• Energy Forms
• Mechanical Energy: The total kinetic and potential energy for an object (or multiple objects)
• Example
• What is the kinetic energy of a 1kg block that is moving with a velocity of 2 m/s?
• Work, Energy Theorem

The work- energy theorem states that the change in the kinetic energy of an object is equal to the net work done in it.

Net Work = ½ mvf^2 – ½ mvi^2

• Potential Energy

GPE = Gravitational Potential Energy

Energy that depends upon the objects position above the earth’s surface.

Equation:     GPE = mgh

GPE = mass * acc due to gravity* height

Units:       joules

• Example
• What is the gravitational potential energy of a 2 kg object that is raised to height of 10 m?
• GPE = mgh
• GPE = 2(9.8)(10)
• GPE = 196 J
• Conservation of Energy

Law of Conservation of Energy:

Within a closed, isolated system, energy can change form, but the total amount of energy is constant. Energy can not be created or destroyed. Ex. Kinetic to Potential Energy

• Questions about Energy
• 1. An object is being lifted up. Is the object’s GPE increasing or decreasing?
• 2. A rock is falling down. As it is falling down, what is happening to its GPE? As it is falling down, what is happening to its KE?
• 3. What happens to the KE of an object when: a) mass is doubled b) velocity is doubled c) velocity is halved
• Conservation of Mechanical Energy

• Mechanical energy is always conserved in a closed system (no friction)
• a decrease in potential energy is accompanied by an increase in kinetic energy.

Formula:  KE_i + PE_i = KE_f + PE_f

• Problem

A large chunk of ice with a mass of 15 kg falls from a roof 8m above the ground. Find the KE of the ice when it reaches the ground. What is the speed of the ice when it reaches the ground?

KE + PE (initial) = KE + PE (final)

knight912@gmail.com }  Energy - the ability to do work  -  The SI unit for energy is the joule (J) (a scalar quanitity) }  Potential Energy - Energy of position or stored  -  An object gains gravitation potential energy when it is lifted from one level to a higher level.  Therefore, gravitation potential energy is directly proportional to the objects height.  PE=U=m*g*h }  Kinetic Energy - Energy of motion  -  The kinetic energy varies with the square of the objects speed.  KE=1/2(mv^2) }  The Law of Conservation of Energy -  states that energy is not created or destoryed.  The total amount of mechanical energy remains constant if no work is done by any force other than gravity.

Energy

The work- energy theorem states that the change in the kinetic energy of an object is equal to the net work done in it.

Net Work = ½ mvf^2 – ½ mvi^2

• Potential Energy

GPE = Gravitational Potential Energy

Energy that depends upon the objects position above the earth’s surface.

Equation:     GPE = mgh

GPE = mass * acc due to gravity* height

Units:       joules

• Example
• What is the gravitational potential energy of a 2 kg object that is raised to height of 10 m?
• GPE = mgh
• GPE = 2(9.8)(10)
• GPE = 196 J
• Conservation of Energy

Law of Conservation of Energy:

Within a closed, isolated system, energy can change form, but the total amount of energy is constant. Energy can not be created or destroyed. Ex. Kinetic to Potential Energy

• Questions about Energy
• 1. An object is being lifted up. Is the object’s GPE increasing or decreasing?
• 2. A rock is falling down. As it is falling down, what is happening to its GPE? As it is falling down, what is happening to its KE?
• 3. What happens to the KE of an object when: a) mass is doubled b) velocity is doubled c) velocity is halved
• Conservation of Mechanical Energy

Notes-Review Kinetic and PE.

Emphasis on conservation of energy.

} Mechanicl energy - The total kinetic and potential energy of an object (or objects) }  The work energy theorem states that the change in the kinetic energy of an object is equal to the net work done on it. }  Mechanical energy is always conserved in a closed system (no friction).  This means that a decrease in the GPE is acompanied by an increase in the KE  }  the GPE lost  = the KE gained 5.  Energy questions: a)  An object is being lifted up.  Is the GPE increasing or decreasing?  b)  A rock is falling down.  As it is falling, what happens to its GPE?  (the KE) c.  A large chuck of ice with a mass of 15 kg fall from a roof 8 m above the ground.  Find the KE of the ice when it reaches the ground and its speed.

Jan. 23

Goal: be able to solve for W, P, t, F, d, KE, and PE

Goal: understand that energy is conserved although it can change forms

Goal: understand that work occurs when a force is applied to an object and it moves (not at right angles to each other)

Kinetic energy assignment

Work, power, energy packet

Jan. 24

Goal: be able to solve for W, P, t, F, d, KE, and PE

Goal: understand that energy is conserved although it can change forms

Goal: understand that work occurs when a force is applied to an object and it moves (not at right angles to each other)

Energy work power warm up packet-make sure you do a few problems a day until the test-first three questions

Conservation of energy assignment

Jan. 25

Goal: be able to solve for W, P, t, F, d, KE, and PE

Goal: understand that energy is conserved although it can change forms

Goal: understand that work occurs when a force is applied to an object and it moves (not at right angles to each other)

Energy work power warm up packet

Conservation of energy ws II

Jan 26

Goal: be able to solve for W, P, t, F, d, KE, and PE

Goal: understand that energy is conserved although it can change forms

Goal: understand that work occurs when a force is applied to an object and it moves (not at right angles to each other)

Start CPO energy Lab-roller coaster lab-Students will determine the KE and PE of a steel marble at various points. This lab will take several periods to complete

Jan. 27

Goal: be able to solve for W, P, t, F, d, KE, and PE

Goal: understand that energy is conserved although it can change forms

Goal: understand that work occurs when a force is applied to an object and it moves (not at right angles to each other)

Finish lab (CPO energy Lab)

Jan. 30

Goal: be able to solve for W, P, t, F, d, KE, and PE

Goal: understand that energy is conserved although it can change forms

Goal: understand that work occurs when a force is applied to an object and it moves (not at right angles to each other)

Warm up packet-conservation of energy problems

Work, power notes

Energy ws -> Kinetic and potential energy

• Energy
• Energy is sometimes defined as the ability to do work.
• Energy is a scalar
• Work is a scalar
• Work

Work- the product of the force exerted on an object and the distance the object is moved in the direction of the force.

Ex. Carrying an object

Formula:          Work = Force x distance

Units: Joules

Also: Work = Force x distance x cosq

*when there is an angle of force.

• Work
• Work is done on any object when a force is applied to it and it moves (has a displacement). If the force applied and the displacement of the object are perpendicular to each other, NO work is done on the object.
• The Work-Kinetic Energy Theorem
• The net work done on an object is equal to the object’s change in kinetic energy.
• Formula Wnet = DKE or W = KEf – Kei
• Example
• Due to friction, a sliding sled’s kinetic energy drops from 300 J to 50 J. What work (net) is done on the sled?
• Wnet = KEf – KEi
• Wnet = 50 – 300
• Wnet = -250 J
• What does the negative sign mean?
• Work Continued
• A negative sign on work means that the work done on the object caused it to slow down, or was directed against an object’s motion.
• Power

Power- the rate at which energy is transferred.

Formula:          Power = Work/time

Units:       Watts

• Power
• The higher the power output, the more quickly work is done
• Brain food: one hp = 750 Watts

Assignment-work I

Jan. 31

Goal: be able to solve for W, P, t, F, d, KE, and PE

Goal: understand that energy is conserved although it can change forms

Goal: understand that work occurs when a force is applied to an object and it moves (not at right angles to each other)

Assignment-power I

Feb. 1

Goal: be able to solve for W, P, t, F, d, KE, and PE

Goal: understand that energy is conserved although it can change forms

Goal: understand that work occurs when a force is applied to an object and it moves (not at right angles to each other)

Power lab-students will determine their own power output

Work power energy test coming soon (next week)

Review ws

Feb. 2

Goal: be able to solve for W, P, t, F, d, KE, and PE

Goal: understand that energy is conserved although it can change forms

Goal: understand that work occurs when a force is applied to an object and it moves (not at right angles to each other)

Work II

Feb. 3

Goal: be able to solve for W, P, t, F, d, KE, and PE

Goal: understand that energy is conserved although it can change forms

Goal: understand that work occurs when a force is applied to an object and it moves (not at right angles to each other)

Test-work power and energy coming soon

W,P,E assignment

Feb. 6

Goal: be able to solve for W, P, t, F, d, KE, and PE

Goal: understand that energy is conserved although it can change forms

Goal: understand that work occurs when a force is applied to an object and it moves (not at right angles to each other)

Work power energy kahoot

Feb. 7

Goal: be able to solve for W, P, t, F, d, KE, and PE

Goal: understand that energy is conserved although it can change forms

Goal: understand that work occurs when a force is applied to an object and it moves (not at right angles to each other)

Work power energy test

Feb. 8

Goal: be able to solve for f, T, v, fd

Goal: understand that waves transfer energy

Goal: understand the Doppler effect

Waves notes-ending with a waves video

Waves        

A wave transfers energy from place to place without transferring matter

Waves travel through a medium (a substance). All waves need a medium except electromagnetic waves, which can travel through a vacuum.

Transverse Waves

Wave where the medium moves at right angles to the wave.

Parts of a Transverse Wave

Crest - highest point of wave

Trough - lowest point of wave

Wavelength - distance between one point in a wave and the exact point on the next wave. Ex. Crest to Crest

Amplitude - distance from crest to middle

Compresional Waves

Compression Waves are waves that the media and waves vibrate in the same direction. Otherwise known as longitudinal waves Ex. Sound

Compression Waves

Compression - compact area of wave

Rarefaction - less dense area of Compression Wave

A Wavelength of 1 Compression Wave consists of 1 Compression and 1 Rarefaction

Wave Frequency and Velocity

Frequency (Hz) - the number of wavelengths in one second, expressed in a unit called Hertz( 1 wavelength per 1 second) Frequency = 1/ period

Period (s) = 1 / frequency or the time of one wavelength.

Velocity (m/s) = Wavelength x Frequency

                   V= f x l(lambda) symbol for wavelength (measured in meters)

Example Problems

A mosquito beats its wings 200 times in 2 seconds. Find its frequency and period

An object vibrates back and forth 4 times in four seconds and produces waves. Each crest has an amplitude of 2 m and the crests are separated by 3 m. Find the velocity of the wave.

Interference

Constructive Interference-when waves meet crest to crest or trough to trough, an additive effect.

Destructive Interference- when the crest of one wave fills in the trough of another wave, a canceling effect.

Interference Examples

Two different waves interfere with each other. One wave has an amplitude of 3 m, the other 2 m.

What is the resulting amplitude if the two waves meet in phase (crest to crest)?

What is the resulting amplitude if the two waves meet out of phase (crest to trough)?

Standing Waves

Standing Wave – wave where certain parts of the wave remain stationary due to interference.

Nodes- stationary parts of a standing wave

Antinodes- positions on a standing wave with the largest amplitudes. They occur halfway between the nodes.

Harmonics

A type of standing wave produced when destructive interference produces a point with no movement and constructive interference produces a point with maximum displacement.

Harmonics

1^st harmonic   2^nd harmonic     3^rd harmonic                              

Doppler Effect

Doppler Effect- change in frequency due to the motion of the source or observer. Named after the Austrian scientist Christian Doppler.

• The greater the speed of the source (or observer) the greater the Doppler Effect.Doppler EffectFrequency detected = frequency of source x (velocity of wave + velocity of detector) / (velocity of wave - velocity of source)Where:vd is negative if the detector is moving away from the sourcevs is negative if the source is moving away from the detectorA mosquito is flying towards you with a velocity 10 m/s while beating its wings with a frequency of 500 Hz. You are moving away from the mosquito with a velocity of 2 m/s. What frequency of sound do you hear?   Goal: be able to solve for f, T, v, fdGoal: understand the Doppler effect What is SoundSound is a longitudinal wave (compression wave)Pitch - highness or lowness of sound due to frequency of sound, high frequency - high pitch   low frequency - low pitch. Low Pitch – fog hornBeatsEx. A 200 Hz sound and a 203 Hz sound will produce a beat frequency of . . . Lab-musical tone-investigating frequency and wavelength Feb. 10Goal: understand that waves transfer energy Rubber 60m/s     Air (0 deg C) 331Water (25deg C) 1498 m/sWood 3850   Glass 4540Stone 5971Humans have 3 parts to their ears. Outer, Middle, and Inner Ears.Middle intensifies the vibrations with 3 bonesMusicNoise - No Pattern or Pitch.Music Cont’dOvertones have frequencies that are multiples of original frequencies Ex. Musical NotesMusic Cont’dBow Waves and Shock WavesShock wave- similar to a bow wave, but a shock wave is produced by overlapping spheres that form a cone. Ex. Super sonic jet. ResonanceNatural Frequency – frequency of vibrations of elastic objects that create their own special sound. Ex. Bells and Tuning forksIntensity and Loudnessloudness is the human perception of sound intensityJet 150, Chain Saw 115, Mower 100, Restaurant 80, Vacuum 75, Whisper 20 Reflection: when a wave strikes a barrier and bounces off 
• Refraction: when a wave goes from one medium to another and bends due to a change in speed
• Reflection and Rarefaction
• Loudness in decibels of various objects
• intensity depends upon the amount of energy in a wave
• Resonance – when a forced vibration matches the objects natural frequency. Ex. Swing                          
• Forced Vibration- vibration of an object that is made to vibrate by another vibrating object that is nearby. Ex. Tuning forks
• Sonic Boom - sharp crack heard on the ground produced by a shock wave.
• Bow wave- A wave in which the crests of the waves overlap the original waves. Ex bug swimming faster in water than the waves produced by the bug. Also speedboat
• Acoustics is the study of sound Ex. Good Acoustics is a Concert Hall or Auditorium.
• Interference is the ability of 2 or more waves to combine to form one.
• Sound Quality describes the differences among sounds. Ex. Violin and Piano
• Resonance - If the sound that reaches an object is at the same frequency as the natural frequency of the object, the object will begin to vibrate at this frequency. Ex. String Insturments
• Using Specific Pitches and Sound Quality by following a regular pattern.
• Inner (fluid filled) sends nerve impulses to brain to be deciphered.
• Outer directs sound to eardrum
• Human Hearing
• Iron 5103     Steel 5200
• Sea Water at 25 deg C. 1531 m/s
• Air (25deg C) 346 m/s Lead 1210
• Complete wave notes
• Goal: understand the Doppler effect
• Goal: be able to solve for f, T, v, fd
•  
•  
•  
•  
• When two sounds are close in frequency, beats may be heard. A beat is heard when you hear a loud sound followed by a faint sound.
• The human ear can hear pitches from about 20 Hz to about 20000 Hz
• High Pitch - piccolo
• Frequency and Pitch
• Sound is caused by waves that are picked up by your ears
• Continue waves notes
•  
• Goal: understand that waves transfer energy
• Feb. 9
•  
•  
• Speed of Sound
• Doppler Effect example problem
• And the velocity of the source (vs) is positive if it is moving towards the detector
• the velocity of the detector (vd) is positive if it is moving towards the source
• Doppler effect formula
• Doppler Effect Formula
• Example:    Fire Engine, Police radar

• Sound Waves: Practical Applications
• Industrial Uses
• High frequency sound waves (ultrasound) is sometimes used as a cleaning tool
• Echo Location
• Sound waves are used as a means of echo location.
• A sound wave is emitted from a source, bounces off obstacles and returns to a receiver
• Medical uses of sound waves
• Sonograms
• Sound waves are used to burst apart mineral deposits in the body (such as kidney or gall stones).
• Disassociation of tumors
• For the test
• Know all 3 of the bones in the middle ear!   This means you must look them up!Assignment-waves ws  Feb. 13Goal: understand that waves transfer energy Waves II ws Goal: be able to solve for f, T, v, fdGoal: understand the Doppler effectSound waves lab-properties of sound waves.Review wsFeb. 15Goal: understand that waves transfer energy Doppler effect ws Goal: be able to solve for f, T, v, fdGoal: understand the Doppler effectWaves notes-from moodleWaves practice problemsFeb. 17Short activity/lab-Transverse waves vs compression waves-shown with a slinky Goal: be able to solve for f, T, v, fdGoal: understand the Doppler effectDoppler II ws ( a more challenging assignment) Feb. 22Goal: understand that waves transfer energy Quiz next week-probably Wed.   Goal: be able to solve for f, T, v, fdGoal: understand the Doppler effectPhysics and writing-Waves test-Feb. 28Quiz next class-Bring your notes!  Goal: be able to solve for f, T, v, fdGoal: understand the Doppler effectWaves quiz Physics and writing-What have you learned about waves?How to find frequency, velocity, period and wavelengthReview conceptsTest March 2-waves  Goal: be able to solve for f, T, v, fdGoal: understand the Doppler effect Review-constructive and destructive interference, beats, harmonics, compression waves, Doppler effect, transverse waves  Questions on the board to solve:  Feb. 27Goal: understand that waves transfer energy  Test-waves and sound-concepts-free response March 1Goal: be able to solve for f, T, v, index of refractionsNotes-Light
•  
• Goal: understand the nature of light, including reflection and refraction
•  
• Test March 2-waves concepts-MC
• Feb. 28
• Kahoot review-waves
• Goal: understand the Doppler effect
• Goal: be able to solve for f, T, v, fd
•  
• A radio station is broadcasting at 99.5 MHz. Find the wavelength of the wave.
• A visible light ray has a wavelength of 700 nm. Find the frequency.
• Review waves problems-doppler effect, v = lf, f = 1/T, T = 1/f, f = events / time
• Physics and writing assignment-
• Test-waves and sound-free response-on Feb. 28
• Physics and writing assignment-
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• Goal: understand that waves transfer energy
• Feb. 27
•  
• Waves III
• How to find frequency detected
• Review sound waves
• Feb. 23
•  
•  
• Goal: understand that waves transfer energy
• Feb. 24
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•  
• Waves review sheet
• Waves and sound ws
•  
• Goal: understand that waves transfer energy
• Feb. 23
•  
•  
• Test Feb. 28
• Resonance lab-resonance lab using the CPO equipment
• Goal: understand the Doppler effect
• Goal: be able to solve for f, T, v, fd
•  
•  
•  
• Goal: understand that waves transfer energy
• Feb. 21
• Physics project info-boat race and boat race video
• Doppler effect video
•  
• Waves reading activity-from moodle
•  
• Goal: understand that waves transfer energy
• Feb. 16
• Waves test-Feb. 28
• Doppler effect example problems
• Goal: understand the Doppler effect
• Goal: be able to solve for f, T, v, fd
•  
• Students will investigate the properties of sound waves with the aid of a tunning fork
•  
• Goal: understand that waves transfer energy
• Feb 14
•  
• Sound wave demos
• Goal: understand the Doppler effect
• Goal: be able to solve for f, T, v, fd
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• Light
• Nature of Light
  • Light has a dual nature: it behaves as both a particle and a wave.
  • Photons are bundles of electromagnetic energy that do not have mass
  • The wave nature of light can be seen from interference patterns. EM waves are transverse waves.
  • Speed of Light
• Physicist Albert Michelson determined the speed of light in the 1880s. He wanted to determine the speed of the “ether” through which light traveled.
• His experiment showed that the speed of light is about 300 000 km/s or 3.0 x 10⁸   m/s
• The experiment is outlined in fig 27.3 in your book
• Electromagnetic waves
• An electromagnetic wave is (simplified) a self propagating wave that is part electric and part magnetic. It is caused by a moving charge.
  • A more thorough definition: A magnetic field will be produced in empty space if a changing electric field is present. This changing electric field will produce a changing magnetic field which will produce a changing electric field. This process will repeat itself, and thus an electromagnetic wave can self propagate through space.
• The range of electromagnetic waves can be seen in the electromagnetic spectrum.
  • Notice the small portion that is visible light
  • EM wave
• EM spectrum
• EM Waves
• Radiation: the transfer of energy by EM waves
• High frequency EM waves have the greatest amount of energy
• High frequency EM waves behave like a photon and are high energy waves
• Low frequency EM waves behave more like a wave and are lower energy waves
• Visible light is the only part of the EM spectrum that humans can see
• Polarization
• The aligning of vibrations of a transverse wave. This is usually accomplished by filtering.
• Example: polarized sun glasses.  Goal: understand the nature of light, including reflection and refraction  Waves concepts test-multiple choice-next class March 3Goal: be able to solve for f, T, v, index of refractionsLight notes
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• Goal: understand the nature of light, including reflection and refraction
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• Waves review II assignment
• Review waves concepts
• Light ws
• Goal: be able to solve for f, T, v, index of refractions
• March 2
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• Light Facts

• Visible Light is an electromagnetic wave that the human eye can detect.
• Different light wavelengths are seen as different colors.
• A ray is a straight line that represents the path of a light beam.
• Speed of Light (c) = 3.0 x 10⁸ m/s

• Light and MatterEx. Glass, plastic, Opaque- absorb or reflect all light waves that fall on them. Ex. Brick
• Translucent – transmit light but objects are not seen clearly. Ex. Frosted glass
• Transparent- objects that transmit light waves

• The visible spectrum of Light
• ColorPrimary colors – red , green , blue
• Secondary colors – yellow, cyan, and magenta
• Colors of the spectrum are associated with specific light wavelengths

• Polarization of lightEx. Sunglasses
• Polarization of light – light in which the electric fields are all in the same line.Light can be polarized because it is a transverse wave.

• ReflectionLaw of Reflection- when a light ray strikes a reflecting surface, the angle of reflection is equal to the angle of incidence. Ex . Laser beamRegular Reflection- when light rays are reflected in one direction. Ex. Smooth surface
• Diffuse Reflection- when light rays are reflected in many directions. Ex Rough surface
• Reflection: When an electromagnetic wave (or any other type of wave) “bounces” off of a surface. All waves show reflection.

• Regular Reflection Example
• Diffuse Reflection Example
• RefractionRefraction of light- bending of light due to the speed of light in different media. Ex Fish tankn_i sin q_I = n_r sin q_r ( where n = the index of refraction of the mediumr = refracted (“second”)
• i = incident (“first”)
• Snell’s Law- a ray of light bends in such a way that a ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant.
• Refraction: The bending of a wave as it passes from one medium to another medium. All waves refract when they enter new mediums

• Snell’s Law Example problem
• A beam of light in a vacuum tube hits a diamond barrier at an angle of 30 degrees (this is the angle of incidence). What is the angle of refraction?
• Make sure your calculator is in degree mode!
• Index of Refractions for various substances
• Indices of RefractionVacuum                         1.0Water                             1.33Crown glass                   1.52Flint glass                       1.61
• Diamond                        2.42
• Quartz                            1.54
• Ethanol                          1.36
• Air                                 1.0003
• Medium                         n

• Index of Refraction and Speed of LightEquation:              n_substance = c / v_substance                                       v_s = c / n_s
• or             
• The index of refraction is the ratio of the speed of light in a vacuum to the speed in the medium.

• Examples
• What is the speed of light in ethanol?
• Kayci aims a flashlight at a mirror that is in space. The light hits the mirror and returns in 5 seconds. How far away is the mirror?
• Refraction Examples
• Refraction Examples
• DiffractionDiffraction usually occurs when waves pass through small openings (like slits), around obstacles, or sharp edges
• Diffraction occurs with all waves
• Diffraction is the spreading of waves into a space or region behind an obstacle.

• Common conversions
• 1 MHz = 10⁶ Hz
• 10⁹ nm = 1 m
• 100 cm = 1 m
• 1000 g = 1 kg
• 1000 m = 1 km March 6Goal: be able to solve for f, T, v, index of refractionsNotes and diagrams of the following two questions about refraction:how does light bend when it goes from a less dense medium to a more dense medium (like air into water)?How does light bend when it goes from a dense medium to a medium that is not very dense?  Goal: understand the nature of light, including reflection and refraction, and snell’s law Snells law ws March 8Goal: be able to solve for f, T, v, index of refractions   Buoyancy lab Goal: understand the nature of light, including reflection and refraction, and snell’s law EM Waves                        Any object above absolute zero gives off ___________________ radiation. Infrared radiation has a wavelength slightly ______________ than visible light. Light (visible radiation) is the only part of the EM spectrum that you can ______________.Review refraction concepts:  March 20Goal: be able to solve for f, T, v, index of refractionsLight ws-problems  Goal: understand the nature of light, including reflection and refraction, and snell’s law         Goal: know the EM spectrumLight ws-concpets Goal: understand the nature of light, including reflection and refraction, and snell’s law         Goal: know the EM spectrumSnell’s laws diagrams-assignment-students must use a protractor to find the angle of incidence. They will than use snell’s law to find the angle of refraction. A protractor is than used to measure and draw the angle of refraction. This assignment will take two class periodsMarch 23Goal: be able to solve for f, T, v, index of refractions Finish snell’s laws diagrams ws Goal: understand the nature of light, including reflection and refraction, and snell’s law         Goal: know the EM spectrumHalf of a light wsMarch 27Goal: be able to solve for f, T, v, index of refractions  Goal: understand the nature of light, including reflection and refraction, and snell’s law         Goal: know the EM spectrum-physics: convection, conduction, radiation, refraction, and refelction March 29Goal: be able to solve for f, T, v, index of refractions Review ws due next class  Goal: understand the nature of light, including reflection and refraction, and snell’s law         Goal: know the EM spectrumTest-waves and lightMarch 31Goal: be able to use ray diagrams to find the proper location of an imageNotes-lenses and mirrorsTest april 10?Intro Notes-Mirrors a.    Flat mirrors are the simplest type of mirror. b.   The image formed appears to be the same size as the object c.    The object and image distance appears to be equal. d.   Flat mirrors form virtual images Virtual image: an image formed by rays of light that appear to intersect at a point behind the mirror. Example: When you look in a mirror, it appears that your reflection is behind the surface of the mirror.A concave mirror is curved inward and converges incoming light rays.A real image can be projected on a surface. A real image is formed when rays of light actually intersect at a single point.Concave mirrors can magnify an object’s image (either smaller or larger)Convex MirrorsConvex mirror
• A convex mirror is an outwardly curved mirror that diverges incoming light rays Convex mirrors always produce virtual images. Convex mirrors provide a large field of view but produce a small image An example is your car mirror-“objects may be closer than they appear.”
• Concave spherical mirrors
• Virtual images can also be seen with concave mirrors.
• Concave mirrors can focus light to produce real images.                                     
• Concave Spherical mirrors
• Flat Mirror
• Demonstration of convex and concave mirrors-real and virtual images
• Assignment-intro to thin lenses
• Goal: understand the characteristics of lenses and mirrors and the images they produce
• Goal: be able to solve for object distance, image distance, and magnification
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• Goal: be able to solve for f, T, v, index of refractions
• March 30
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• Test next March 30
• Review for the test with a kahoot review
•          Goal: know the EM spectrum
• Goal: understand the nature of light, including reflection and refraction, and snell’s law
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• Light-super fun ws-this assignment covers all of the topics for the light unit
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• Goal: be able to solve for f, T, v, index of refractions
• March 28
• Light ws-concepts
•          Goal: know the EM spectrum
• Goal: understand the nature of light, including reflection and refraction, and snell’s law
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• Goal: be able to solve for f, T, v, index of refractions
• March 24
• Test-Light-Moved to march 30
• Review light concepts
•          Goal: know the EM spectrum
• Goal: understand the nature of light, including reflection and refraction, and snell’s law
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• Goal: be able to solve for f, T, v, index of refractions
• March 22
• Test-March 26
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• Goal: be able to solve for f, T, v, index of refractions
• March 21
•          Formulas to use: v = lf and d = vt
•          Goal: know the EM spectrum
• Goal: understand the nature of light, including reflection and refraction, and snell’s law
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• You are stuck on an island. To survive, you must hunt fish with a ray gun (shoots light). While standing on a cliff, you notice a fish in the water. How should you aim your ray gun?
• You are stuck on an island. To survive, you must hunt fish with a spear. While standing on a cliff, you notice a fish in the water. How should you aim a spear to catch the fish?
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• Radio waves have low frequencies and long wavelengths. Microwaves are radio waves with _______________ frequencies. Microwave ovens use ________________. In a microwave oven, microwaves transfer energy to an object (what you are cooking) and causes the kinetic energy of the object to increase.
• In 1905, Albert Einstein hypothesized that light was composed of tiny particles called _______________ . So is light (and other EM waves) a particle or a wave? The answer is _______________________. Light has a _________________ nature. EM waves behave as both a particle and a wave. Low frequency and long wavelength EM waves tend to behave more as a ______________. High frequency and short wavelength EM waves tend to behave more as a photon (particle). High frequency EM waves have the greatest photon energy.
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• The shorter the wavelength of an EM wave, the _______________ the frequency. As the frequency of an EM wave _________________ the amount of energy carried by the wave increases. The electromagnetic spectrum arranges EM waves in order of wavelengths.
• Electrically charged particles produce_____________waves. EM waves are sometimes referred to as electromagnetic radiation. EM waves are_______________ waves. The transfer of energy by EM waves is called __________________. EM waves can travel through a ____________ at a speed of 3 x 10⁸ m/s. Thus, all EM waves will travel at the same speed in a vacuum.
• EM waves notes:
• Goal: be able to solve for f, T, v, index of refractions
• March 10
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• Buoyancy notes
• March 9
• Snell’s law lab
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• Goal: understand the nature of light, including reflection and refraction, and snell’s law
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• Light test-March 26?
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• Goal: be able to solve for f, T, v, index of refractions
• March 7
• Index of refraction assignment
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•  
• Goal: understand the nature of light, including reflection and refraction, and snell’s law
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• Thin Lenses-Intro Notes
• A lens forms images by refracting (bending) light while a mirror reflects light
• The Focal Point
• Light rays from an object that is very far away are nearly parallel
• The focal point of a lens is the place where the refracted light waves from a distant object converge (or appear to converge)
• The focal length
• The focal length is the distance from the focal point to the center of the lens
• Converging Lens
• A converging Lens is thicker in the middle. A converging lens will refract light waves so that they will “converge” to form an image.
• Also called a convex lens
• Converging Lens
• A converging lens can produce a real or virtual image
• When an object is located at a distance that is greater then the focal length, the image produced is real.
• Converging Lens
• When the object is located at a distance that is between the lens and the focal point, the image is virtual
• Diverging Lens
• A diverging lens is thinner in the middle. Rays of light that pass through a diverging lens will refract outward
• Also called a concave lens
• Diverging Lens
• A diverging lens will produce only virtual images
• The image produced will be smaller than the object
• The image will be inside of the focal point
• Examples of Converging and Diverging Lenses   
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• Thin-Lens Equation
• 1/p + 1/q = 1/fp = distance from object to lensf = focal length
• q = distance from image to lens
• Where:

• Signs For Lensesp is negative when the object is in back of the lens
• p is positive when the object is in front of the lens

• Signs for lensesq is negative when the image is in front of the lens
• q is positive when the image is in back of the lens

• Signs for lensesf is negative for a diverging lens
• f is positive for a converging lens

• Example Problem
• An ant is placed 2 cm in front of a converging lens that has a focal length of 1 cm. What is another name for this lens? Where is the image located?   
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dvalde4@neisd.net

valde4@neisd.net

April 1

Mirrors lab

Finish thin lens intro ws

April 3

Goal: be able to solve for object distance, image distance, and magnification

Goal: be able to use ray diagrams to find the proper location of an image

Goal: understand the characteristics of lenses and mirrors and the images they produce

Demonstration of real and virtual images with a concave mirror and a candle

Thin lens ws

April 4

Goal: be able to solve for object distance, image distance, and magnification

Goal: be able to use ray diagrams to find the proper location of an image

Goal: understand the characteristics of lenses and mirrors and the images they produce

Thin lens lab-students will find the image location and size with a convex lens, candle, and a screen

April 5

Goal: be able to solve for object distance, image distance, and magnification

Goal: be able to use ray diagrams to find the proper location of an image

Goal: understand the characteristics of lenses and mirrors and the images they produce

Ray diagram notes

Lens rules for ray diagrams:

#1 Draw a ray of light from the top of the object to the center of the lens. This beam must be parallel to the principle axis. Once at the center of the lens, the beam will refract. Continue the line so that it goes through the focal point.

#2 Draw a ray of light from the top of the object so that it goes through the exact center of the lens.

Ray diagrams ws

April 6

Goal: be able to solve for object distance, image distance, and magnification

Goal: be able to use ray diagrams to find the proper location of an image

Goal: understand the characteristics of lenses and mirrors and the images they produce

Lens, mirrors, light concepts ws

Test delayed until April 10

April 7

Review light

Review ws due next class

Test April 10 class

April 10

Goal: be able to solve for object distance, image distance, and magnification

Goal: be able to use ray diagrams to find the proper location of an image

Goal: understand the characteristics of lenses and mirrors and the images they produce

Turn in review ws

Test-lenses, light, mirrors

April 11

Goal: use coulomb’s law to solve for F, q, or d

Goal: understand how charges are transferred

Notes-static electricity

• Electrostatics
• Charge
• There are two kinds of charges
  • Positive
  • Negative
  • Charge
• Electrons are negatively charged
• Protons are positively charged
• Charge
• Like charges repel

       Example: protons repel protons

• Unlike Charges attract
• Example: Protons attract electrons
• Charge
• Electric charge is conserved
• Charges can be transferred, but or not created nor destroyed
• Charge
• Electric Charge is quantized (it has a value).
• An electron has a charge of

-1.6 x 10^-19 C

• Charge
• There are 6.2 x 10¹⁸ electrons in –1 C
• Transfer of Charge Conductors
• Conductor: material that transfers charge easily. Electrons are not held tightly to the nucleus
• Transfer of Charge Insulators
• Insulators: a material that does not transfer charge easily. Insulators hold their electrons more tightly. A poor conductor of electricity.
• Transfer of Charge Charging by Contact
• Charging by contact
• The transfer of electrical charges by objects in contact.
• Transfer of Charge         Induction
• Induction: The charging of an object without direct contact from another object.
• Induction Example
• Transfer of Charge Induction
• Example of induction: A negatively charged rod is moved close to a metal sphere of neutral charge that is attached to Earth. The negative rod will repel the electrons in the sphere.
• Transfer of Charge Induction
• The electrons in the sphere will be repelled by the negatively charged rod and will move to the Earth. The sphere will have uniformly distributed positive charges on its surface.
• Transfer of Charge Polarization
• When a charged object is brought next to a neutrally charged insulator, polarization occurs.
• Transfer of Charge Polarization
• Polarization: The presence of a charged object will cause another object’s charges to realign. One side of the object will be more positive and the other more negative.
• Grounding
• An object is considered to be grounded if it is attached to the Earth.
• Grounded: attaching an object to the Earth to eliminate excess charge.
• Coulomb’s Law
• F = k q₁q₂

                                   r²

Where k = 8.99 x 10⁹ N m² / C²

• Coulomb’s Law Example Problem

A large harvester ant has accumulated 6 mC of charge. A large atta major has accumulated 10 mC. The atta is to the left of the harvester. The two ants are separated by 2 cm. What is the force on the atta ant?

April 12

Goal: use coulomb’s law to solve for F, q, or d

Goal: understand how charges are transferred

Coulombs law ws

April 13

Goal: use coulomb’s law to solve for F, q, or d

Goal: understand how charges are transferred

Statics demo

April 17

Current electricity and circuits notes

• CURRENT ELECTRICITY
• Current

Electric Current (I)- A flow of charged particles, usually electrons. Units for I are amperes (A or amps).

Current that flows in one direction is direct current (DC)

Current that alternates direction is alternating current (AC)

• Potential Difference
• Another term for potential difference (V) is voltage (V)
• Units-volts (V)
• The voltage measures the electric potential difference between two points.
• Electric current will flow from high to low potential-the greater the difference, the greater the electron flow.
• Potential Difference Sources Examples

Voltaic Cell- dry cell that converts chemical energy into electric energy.

Battery- several dry cells together to produce electric energy from chemical energy

Photovoltaic- solar cell, converts light energy to electric energy.

Generators, power plants

• Ohm’s Law

Resistance- property that determines how much current will flow .

Ohm’s Law Equation:       I = V/R or V = IR

Resistance = Voltage / Current

Units for resistance = Ohm’s W

Resistors- devices designed to have a specific resistance. Ex. Potentiometer (variable resistor or rheostat)

• Ohm’s Law continued
• Conductors have little resistance to electron flow
• Insulators have great resistance to electron flow.
• Electric Circuit

Electric Circuit- charges moving around a closed loop from a pump(battery) back to the pump.

There are two basic types of circuits:

series               and               parallel.

There is only one path or branch for electron flow in a series circuit. There are multiple branches or paths in a parallel circuit.

.

• Electric Power

Electric Power- the product of voltage x current.

Equation:  P = V x I

Power = Voltage x Current   Units: Watts

The unit for current is the ampere.

1 ampere = 1 Coulomb/ second

Found by a French scientist Andre Ampere

• Energy Transfers in Circuits

Equation:  Power = Current² x Resistance

When a capacitor is charged or discharged through a resistor, the current is high initially and falls to 0

The energy transferred is the product of power and time.

Equation: Energy = I²Rt

• Transmission of Electric Energy

High voltage transmission lines carry electrical energy over long distances with minimal loss of energy. Ex. Power Plants

The kilowatt-hour is a unit of energy.

Energy = Power x time (units: kilowatt-hour)

April 18

Circuits notes:

The electric current in a series circuit has only one path to follow. This means that the current at any point in a series circuit is the ____________________________

Example of a series circuit:

1. The total resistance of the circuit.

1. The total current flowing through the circuit

1. Fill in the chart using ohm’s law:

1. The voltage drop across the 2 W resistor

1. the current through the 3 W resistor

Parallel Circuits

Any resistors connected in parallel connect to the same two points. Therefore, resistors connected in parallel have the same ________________________.

Find the equivalent resistance of the circuit

Fill in the chart using ohms law:

What is the potential difference across the 4 W resistor?

What is the current through the 2 W resistor?

Review:

When you add a resistor in series the total resistance of a circuit ___________________

When you add a resistor in parallel, the total resistance of a circuit ________________

Adding a resistor in series will ____________________ the current through the circuit

Adding a resistor in parallel will ______________the current flowing through the circuit

Three light bulbs are connected in a series. One burns out. The other two ___________

Three light bulbs are connected in parallel. One burns out. The other two ___________

April 19

Current electricity ws

April 21

Review circuits

Series and parallel ws

Electricity test-May 8^th?

Review ws

April 24

Review static electricity

Coulombs law II ws

-Test on May 8^th

April 25

Notes-compound circuits (complex circuits)

Assignment CD 34-1

Assignment CD 34-2

April 26

***You may use one 3x5 note card on the final exam. All information on the note card must be written by your own hand.***

Notes-review comound circuits

Assignment CD 35-1

Assignment CD 35-2

April 27

Circuits lab

May 1

Review electricity

May 2

Compound circuts I-finding the current and resistance of individual resistors

May 3

Compound circuts II-finding the current and resistance of individual resistors-3 problems

Test on Tuesday( May 15)

May 4

Notes-thermodynamics

Specific heat ws

Electricity test on May 15

May 8

Review electricity and review ws

Test next class

Please bring book on may 16

May 9

Test-electricity

Please bring book next class

May 10

Fusion and fission assignment-use with book

May 11

Notes-magnets

May 12

Magnets I ws

May 15

Magnetic field notes, diagram, and demonstration

May 16

Notes-Photoelectric effect

May 17

Notes-thermodynamics

May 18

Convection, conduction, radiation demo

Heat energy assignment

May 19

Work on the semester exam review sheet

May 21

Work on the semester exam review sheet

May 22