2012 PVHS NHSPE Review Science Physics Part 1… Energy.

2012 PVHS NHSPE Review2012 PVHS NHSPE ReviewScienceScience

Physics Part 1… EnergyPhysics Part 1… Energy

What we need to know…What we need to know…

1.1. Which of the following examples has the Which of the following examples has the greatest thermal (internal) energy? greatest thermal (internal) energy?

a)a) 5 kg of water with a temperature of 5 kg of water with a temperature of 150°C 150°C

b)b) 8 kg of water with a temperature of 8 kg of water with a temperature of 110°C 110°C

c)c) 10 kg of water with a temperature of 10 kg of water with a temperature of 90°C 90°C

d)d) 100 kg of water with a temperature of 100 kg of water with a temperature of 28°C 28°C

2. 2. A ball is initially dropped from a height 4 meters. A ball is initially dropped from a height 4 meters. After the ball bounces it returns to a height of After the ball bounces it returns to a height of only 2 meters. How much of the ball’s initial only 2 meters. How much of the ball’s initial gravitational potential energy was transformed gravitational potential energy was transformed between the initial position and the final between the initial position and the final position of the ball? position of the ball?

a)a) One fourth of the total energy. One fourth of the total energy.

b)b) Half of the total energy. Half of the total energy.

c)c) Double the total energy. Double the total energy.

d)d) Four times the total energy. Four times the total energy.

3.3. Energy is created as the result which Energy is created as the result which activity? activity?

a)a) Burning gasoline in an internal Burning gasoline in an internal combustion engine. combustion engine.

b)b) Damming a river for hydroelectric Damming a river for hydroelectric power. power.

c)c) Rolling a marble down an incline plane. Rolling a marble down an incline plane.

d)d) Energy can only be transformed, not Energy can only be transformed, not created. created.

4.4. Aluminum was once used as the wires in home construction. Aluminum was once used as the wires in home construction. Recently, it was changed to copper wires. Which of the Recently, it was changed to copper wires. Which of the following statements following statements BESTBEST account for why aluminum was account for why aluminum was replaced with copper? replaced with copper?

a)a) When electrical energy is passed through a copper wire, When electrical energy is passed through a copper wire, less of the energy removes copper atoms from the wire. less of the energy removes copper atoms from the wire.

b)b) The electrical energy that a copper wire can transfer is The electrical energy that a copper wire can transfer is less than less than an aluminum wire. an aluminum wire.

c)c) As a byproduct of transmission, more electrical energy is As a byproduct of transmission, more electrical energy is transformed to wasted thermal energy in aluminum wire transformed to wasted thermal energy in aluminum wire than in copper than in copper

d)d) The electrical energy that passes through an aluminum The electrical energy that passes through an aluminum wire cannot be directed as well as the energy passing wire cannot be directed as well as the energy passing through copper. through copper.

5.5. In an alternating current (AC) circuit, In an alternating current (AC) circuit,

a)a) voltages can be easily increased and decreased voltages can be easily increased and decreased within the circuit allowing for lower energy within the circuit allowing for lower energy losses during transmission. losses during transmission.

b)b) voltages change direction several times a voltages change direction several times a second to generate electrical charge more second to generate electrical charge more rapidly. rapidly.

c)c) rapid current changes regulate the ease at rapid current changes regulate the ease at which electricity passes through the circuit. which electricity passes through the circuit.

d)d) current most often is high to prevent energy current most often is high to prevent energy losses during transmission, but can be low to losses during transmission, but can be low to decrease the voltage in the circuit. decrease the voltage in the circuit.

6.6. Which of the following describes how a dam Which of the following describes how a dam creates electricity? creates electricity?

a)a) Water is heated up and creates steam to turn Water is heated up and creates steam to turn the generator to create electricity. the generator to create electricity.

b)b) Gravitational potential energy transfers to Gravitational potential energy transfers to kinetic energy which turns a generator. kinetic energy which turns a generator.

c)c) Electrons are removed from the water as it Electrons are removed from the water as it passes and creates electricity. passes and creates electricity.

d)d) Water flows over wires in the dam which Water flows over wires in the dam which creates current from the water.creates current from the water.

7.7. A hammer strikes a nail and drives the nail into A hammer strikes a nail and drives the nail into a block of wood. If the action force is the a block of wood. If the action force is the hammer striking the nail, the reaction force is hammer striking the nail, the reaction force is

a)a) the nail striking the wood with an equal and the nail striking the wood with an equal and opposite force. opposite force.

b)b) the nail striking the hammer with an equal the nail striking the hammer with an equal and opposite force. and opposite force.

c)c) the wood striking the hammer with an equal the wood striking the hammer with an equal and opposite force. and opposite force.

d)d) the wood striking the nail with an equal and the wood striking the nail with an equal and opposite force. opposite force.

8.8.Which of the following would Which of the following would supply the greatest acceleration supply the greatest acceleration when applied to a 10 kg mass? when applied to a 10 kg mass?

a)a)5N 5N

b)b)10N 10N

c)c)15N 15N

d)d)20N20N

9.9. Use the diagram to answer the question below. Use the diagram to answer the question below.

A cart is being pulled North across a A cart is being pulled North across a carpeted floor. Which direction is the force carpeted floor. Which direction is the force of friction acting?of friction acting?

a)a)North North

b)b)South South

c)c) East East

d)d)West West

10.10.You have created a track out of cardboard for a You have created a track out of cardboard for a marble to travel down. In order for the marble to marble to travel down. In order for the marble to complete the track, why does the first hill have to be complete the track, why does the first hill have to be the highest? the highest?

a)a) The friction caused by the track resists the The friction caused by the track resists the motion of the marble. motion of the marble.

b)b) The friction caused by the track increases the The friction caused by the track increases the motion of the marble. motion of the marble.

c)c) Gravity is pulling down on the marble causing it Gravity is pulling down on the marble causing it to slow down. to slow down.

d)d) Gravity is pulling down on the marble causing it Gravity is pulling down on the marble causing it to speed up. to speed up.

What is Energy?What is Energy?

Energy is… Energy is… The ability of an object to The ability of an object to

produce a change in itself or produce a change in itself or its environmentits environment

It is a measure of the It is a measure of the capacity to produce change.capacity to produce change.Sometimes Sometimes WorkWork is is

associated with changeassociated with changeWork transfers energy, but Work transfers energy, but

energy can also be energy can also be transferred by transferred by HeatHeat and and RadiationRadiation

Can Energy be Created?Can Energy be Created?

Law of Conservation of EnergyLaw of Conservation of Energy- Energy - Energy cannot be created or destroyedcannot be created or destroyed Total amount of energy is constantTotal amount of energy is constant Energy can only be stored or transferredEnergy can only be stored or transferred

… stretching the bow transfers chemical energy from your muscles into potential energy in the bow and string

… releasing the arrow transfers potential energy in the bow to kinetic energy in the arrow

Energy

Capacity for change

Can’t create or destroy

Store it

Transfer it

Sun

What is the earth’s primary energy What is the earth’s primary energy source?source? The sun releases the energy stored in The sun releases the energy stored in

atoms through atoms through FusionFusion FusionFusion combinescombines the atoms of an the atoms of an

element to create a different elementelement to create a different element Energy is transferred to earth by Energy is transferred to earth by

RadiationRadiation Electromagnetic waves like lightElectromagnetic waves like light Higher frequency… higher energyHigher frequency… higher energy

waves

radiation

light

The sun does not

“burn” and it does not “create” energy

Energy

Capacity for change


Store it

Transfer it

Radiation

Waves

Light

X

Sun

How else can energy transfer?How else can energy transfer? WorkWork transfers energy transfers energy WorkWork is a is a ForceForce that causes displacement that causes displacement

(moves an object a distance)(moves an object a distance) W=FxdW=Fxd Whenever work is done there is Whenever work is done there is FrictionFriction

Friction always opposes motion and causes Friction always opposes motion and causes energy loss to the environmentenergy loss to the environment

Work

Force

Distance

Friction

Remember… Force is a pull or push on an object and is only related to energy by work… energy is not a force

Energy

Capacity for change


Store it

Transfer it

Radiation

Work

Heat

Force

Distance

Thermal Energy

Vibrating atoms and

molecules

Friction

Waves

Light

X

Sun

How else can energy How else can energy transfer?transfer? Heat Heat also transfers also transfers

energyenergy HeatHeat is energy is energy

transferred between transferred between objects at different objects at different temperatures temperatures Higher temp… faster Higher temp… faster

atoms run into Lower atoms run into Lower temp… slower atoms temp… slower atoms

The random motion of The random motion of atoms is atoms is Thermal EnergyThermal Energy

Energy

Capacity for change


Store it

Transfer it

Radiation

Work

Heat

Force

Distance

Thermal Energy

Vibrating atoms and

molecules

Friction

Waves

Light

X

Sun

Thermal EnergyThermal Energy Virtually every energy transfer involves Virtually every energy transfer involves

friction and temperature differencesfriction and temperature differences Some energy is always lost to the Some energy is always lost to the

environment as thermal energyenvironment as thermal energy We try to counteract this by designing We try to counteract this by designing

more efficient devicesmore efficient devices

Energy

Capacity for change


Store it

Transfer it

Kinetic

Objects in motion

Radiation

Work

Heat

Snowboarder

Force

Distance

Thermal Energy

Vibrating atoms and

molecules

Friction

Waves

Light

X

Sun How is energy stored?How is energy stored? Kinetic energy Kinetic energy is the energy stored in the is the energy stored in the

motion of objectsmotion of objects Any object in motion has stored energyAny object in motion has stored energy KE = ½ mass x velocityKE = ½ mass x velocity22

KE energy increases greatly with speedKE energy increases greatly with speed

Energy

Capacity for change


Store it

Transfer it

Kinetic

Objects in motion

Radiation

Work

Heat

Snowboarder

Force

Distance

Thermal Energy

Vibrating atoms and

molecules

Friction

Waves

Light

X

Sun

Thermal Energy is just energy stored Thermal Energy is just energy stored in the kinetic energy of atomsin the kinetic energy of atoms

Energy

Capacity for change


Store it

Transfer it

Potential

Kinetic

Position

Objects in motion

Radiation

Work

Heat

Gravitational

Elastic

Chemical

Spring or Rubber Band

Food

Battery, TNT

Snowboarder

Force

Distance

Thermal Energy

Vibrating atoms and

molecules

Friction

Waves

Light

X

Sun How is energy stored?How is energy stored? PotentialPotential energy is energy stored because energy is energy stored because

of an object’s of an object’s positionposition Examples…Examples…

If you stretch a rubber band, it has more If you stretch a rubber band, it has more energy than its starting positionenergy than its starting position

An object at a higher position has more An object at a higher position has more energy than a similar object at a lower energy than a similar object at a lower positionposition

An electron in a higher orbit has more An electron in a higher orbit has more energy than it did in a lower orbitenergy than it did in a lower orbit

Electricity and magnetism are also Electricity and magnetism are also forms of potential energyforms of potential energy

Energy

Capacity for change


Store it

Transfer it

Potential

Kinetic

Position

Objects in motion

Radiation

Work

Heat

Gravitational

Elastic

Chemical

spring or rubber band

Food

Battery, TNT

Snowboarder

Force

Distance

Thermal Energy

Vibrating atoms and

molecules

Friction

Waves

Light

X

Sun

Energy Transfer Pie ChartEnergy Transfer Pie Chart

Store

Electrical Energy - Eelec

Gravity Potential- PEElastic Potential- Ee

Chemical- Ec

Kinetic Energy – KEThermal Energy - Et

Transfer

Work - WHeat - QRadiation

C

A

B

PE

A

KE

PEWgravity

Wfriction

Et

B

Wgravity

Wfriction KE

Et

C

Practice and DemosPractice and Demos

Create energy transfer pie charts Create energy transfer pie charts for the following processes:for the following processes: Bending a paperclip (on your own)Bending a paperclip (on your own) Movement of a pendulum Movement of a pendulum Solar Panel and motor Solar Panel and motor Spring and cart Spring and cart

Be sure to show what is causing Be sure to show what is causing the energy to transfer.the energy to transfer.

Follow the instructions and use Follow the instructions and use the pie charts in the class set.the pie charts in the class set.

AbbreviationsAbbreviations

StoreStore• PE – Gravity PotentialPE – Gravity Potential• KE – Kinetic EnergyKE – Kinetic Energy

• EEee – Elastic Energy – Elastic Energy

• EEchem chem – Chemical Energy– Chemical Energy

• EEtt – Thermal Energy – Thermal Energy

• EEelecelec – Electrical Energy – Electrical Energy

TransferTransfer• W – Work W – Work • Q – HeatQ – Heat• R - RadiationR - Radiation

******Begin your homework if you finish early ******

Physics Part 2… Physics Part 2… Force and MotionForce and Motion

Rolling Ball Grand PrixRolling Ball Grand Prix

Purpose:Purpose: To observe an object in motion and determine what is To observe an object in motion and determine what is necessary to change that object’s motion.necessary to change that object’s motion.

Materials: Materials: Butcher paper with track, timer, and a large marble.Butcher paper with track, timer, and a large marble. Procedure:Procedure: See who can roll the ball along the track the fastest using See who can roll the ball along the track the fastest using

one finger. one finger.

Rules:Rules: If the marble goes off the track If the marble goes off the track

pick it up and restart where the pick it up and restart where the marble went out. Keep the marble went out. Keep the timer runningtimer running

You can not touch the marble You can not touch the marble at all in the “no touch” zoneat all in the “no touch” zone

Be sure to use only one fingerBe sure to use only one finger Answer the questions on the Answer the questions on the

sheet as you go.sheet as you go.


1.1. Describe the ball’s motion Describe the ball’s motion in the “no touch” zone.in the “no touch” zone.

Moves in a straight lineMoves in a straight line Speed stays about the sameSpeed stays about the same

2.2. What does the ball do in What does the ball do in the corners or around the the corners or around the loop if you don’t push it?loop if you don’t push it?

Wants to keep going in the Wants to keep going in the same directionsame direction

3.3. What can you say in What can you say in general about the motion general about the motion of an object that has no of an object that has no “force”?“force”?

Without a force, objects will Without a force, objects will move in a straight line at the move in a straight line at the same speedsame speed

This is basically This is basically Newton’s 1Newton’s 1stst Law of Law of Motion…Motion…

““An object at rest tends to An object at rest tends to stay at rest and an stay at rest and an object in motion tends object in motion tends to stay in motion with to stay in motion with the same speed and in the same speed and in the same direction the same direction unless acted upon by unless acted upon by an unbalanced force”an unbalanced force”

This is also called the This is also called the Law of InertiaLaw of Inertia InertiaInertia is an object’s is an object’s

resistance to a change in resistance to a change in motionmotion

MassMass is a measure of is a measure of inertiainertia


4.4. How did you get the ball to How did you get the ball to speed up or slow down?speed up or slow down?

Push Harder in the direction it Push Harder in the direction it is rollingis rolling

Push opposite the motionPush opposite the motion

5.5. How did you get the ball to How did you get the ball to change direction?change direction?

Push in the direction you Push in the direction you want the ball to gowant the ball to go

6.6. What would you need to What would you need to do differently if the ball do differently if the ball was twice as large (had was twice as large (had twice the mass)?twice the mass)?

Push harder to get the same Push harder to get the same change in motionchange in motion

ForceForce is any push or is any push or pull on an objectpull on an object To change the ball’s To change the ball’s

motion, you applied force motion, you applied force

Acceleration (a)Acceleration (a) is the is the rate of change in rate of change in velocityvelocity VelocityVelocity is an object’s is an object’s

speed speed andand direction direction ForceForce causes causes accelerationacceleration

which which changes speed or changes speed or directiondirection

Mass Mass measuresmeasures inertia inertia, , or resistance to changeor resistance to change More mass, less More mass, less

accelerationacceleration


ForceForce is any push or is any push or pull on an objectpull on an object To change the ball’s To change the ball’s

motion, you applied force motion, you applied force

Acceleration (a)Acceleration (a) is the is the rate of change in rate of change in velocityvelocity VelocityVelocity is an object’s is an object’s

speed speed andand direction direction ForceForce causes causes accelerationacceleration

which which changes speed or changes speed or directiondirection

Mass Mass measuresmeasures inertia inertia, , or resistance to changeor resistance to change More mass, less More mass, less

accelerationacceleration

This is the 2This is the 2ndnd Law of Law of Motion:Motion: Increase force… Increase force…

increase accelerationincrease acceleration Increase mass… Increase mass…

decrease accelerationdecrease acceleration

(N) Newtonsin measured is Force

m

Faor

mass

ForceonAccelerati


7. Which of the following would require the least amount of force,if applied to the same ball?

a) Stopping the ball that is rolling on a flat and smooth surface.

b) Changing the direction of a ball that is rolling on a flat and smooth surface.

c) Starting the ball in motion on a flat and smooth surface.

d) Keeping the ball moving at a constant speed on a flat and smooth surface.

Answer DAnswer D As the ball rolls there is As the ball rolls there is

a small amount of a small amount of friction… if you don’t friction… if you don’t keep pushing the ball keep pushing the ball will slowwill slow

To keep the ball rolling, To keep the ball rolling, at constant speed you at constant speed you just need to overcome just need to overcome frictionfriction

A, B, and C require a A, B, and C require a change in motionchange in motion

To change the balls To change the balls motion, you need to motion, you need to overcome both inertia overcome both inertia and frictionand friction


7.7. What would happen if two What would happen if two object’s were racing on the object’s were racing on the same track and they same track and they collided?collided?

Each would change speed Each would change speed and/ or direction… requires and/ or direction… requires forceforce

They exert force on each They exert force on each otherother

The forces are in opposite The forces are in opposite directionsdirections

This is the 3This is the 3rdrd Law of Motion… Law of Motion…

““For every action there is an equal For every action there is an equal and opposite reaction”and opposite reaction”

Forces always occur in pairs Forces always occur in pairs that are equal and in opposite that are equal and in opposite directionsdirections

Examples…Examples…The earth exerts a 600N force on you, you exert The earth exerts a 600N force on you, you exert

the same force on the earththe same force on the earth

A Bat hits a ball, the ball hits the bat with the A Bat hits a ball, the ball hits the bat with the same forcesame force

Force Force

A hammer strikes a nail and drives the nail into a A hammer strikes a nail and drives the nail into a block of wood. If the action force is the hammer block of wood. If the action force is the hammer striking the nail, the reaction force is striking the nail, the reaction force is

a)a) the nail striking the wood with an equal the nail striking the wood with an equal and opposite force. and opposite force.

b)b) the nail striking the hammer with an the nail striking the hammer with an equal and opposite force. equal and opposite force.

c)c) the wood striking the hammer with an the wood striking the hammer with an equal and opposite force. equal and opposite force.

d)d) the wood striking the nail with an equal the wood striking the nail with an equal and opposite force. and opposite force.

Graphs of MotionGraphs of Motiondis

tan

ce

velo

city

acc

ele

rati

on

time time time

Constant acceleration

No acceleration

ForceForce

What is a Net What is a Net force?force?

Net Force = sum of all force vectorsNet Force = sum of all force vectors

ForceForce

What is a Net What is a Net force?force?

Net Force = sum of all force vectorsNet Force = sum of all force vectors

Balanced Forces…•No Net Force•What happens?

Unbalanced Forces…•Net Force•What happens?

*Cart will Accelerate to the right*Nothing changes

ForceForce

How are How are forces forces different?different?

Types of forces:Types of forces: Contact forces-Contact forces- forces that forces that

happen when two objects happen when two objects touchtouch

Field Forces- Field Forces- objects don’t objects don’t touch but they still push or touch but they still push or pull each other pull each other (Action-at-a-(Action-at-a-distance)distance)

Types of ForcesTypes of Forces

Contact Forces Field Forces

Frictional Force Gravitational Force

Tensional Force Electrical Force

Normal Force Magnetic Force

Air Resistance Force

Applied Force

Spring Force

Electrical force and magnetism are the same as gravity in varying with distance

Field Forces

Gravitational Force Any object with mass creates

gravitational force… more mass, more force

the closer the object, the greater the force…

The force decreases rapidly as distance increases

Small force

Much Bigger force

What we need to know…What we need to know…

1.1. Which of the following examples has the Which of the following examples has the greatest thermal (internal) energy? greatest thermal (internal) energy?

a)a) 5 kg of water with a temperature of 5 kg of water with a temperature of 150°C 150°C

b)b) 8 kg of water with a temperature of 8 kg of water with a temperature of 110°C 110°C

c)c) 10 kg of water with a temperature of 10 kg of water with a temperature of 90°C 90°C

d)d) 100 kg of water with a temperature of 100 kg of water with a temperature of 28°C 28°C

1.1. Which of the following examples has the greatest Which of the following examples has the greatest thermal (internal) energy? thermal (internal) energy?

a)a) 5 kg of water with a temperature of 150°C 5 kg of water with a temperature of 150°C

b)b) 8 kg of water with a temperature of 110°C 8 kg of water with a temperature of 110°C

c)c) 10 kg of water with a temperature of 90°C 10 kg of water with a temperature of 90°C

d)d) 100 kg of water with a temperature of 28°C 100 kg of water with a temperature of 28°C

D… temperature measures the D… temperature measures the averageaverage kinetic energy. kinetic energy. To determine the greatest amount of energy, you To determine the greatest amount of energy, you need to consider mass or matter. Since it is all the need to consider mass or matter. Since it is all the examples are the same substance, just multiply the examples are the same substance, just multiply the mass x temperature. Thermal energy is where all mass x temperature. Thermal energy is where all energy in a physical process ends up… the random energy in a physical process ends up… the random motion of atoms and molecules… this point should motion of atoms and molecules… this point should be emphasized since several sample test questions be emphasized since several sample test questions allude to this.allude to this.

22. A ball is initially dropped from a height 4 . A ball is initially dropped from a height 4 meters. After the ball bounces it returns meters. After the ball bounces it returns to a height of only 2 meters. How much to a height of only 2 meters. How much of the ball’s initial gravitational potential of the ball’s initial gravitational potential energy was transformed between the energy was transformed between the initial position and the final position of initial position and the final position of the ball? the ball?





22. . A ball is initially dropped from a height 4 meters. After the ball A ball is initially dropped from a height 4 meters. After the ball bounces it returns to a height of only 2 meters. How much of bounces it returns to a height of only 2 meters. How much of the ball’s initial gravitational potential energy was transformed the ball’s initial gravitational potential energy was transformed between the initial position and the final position of the ball? between the initial position and the final position of the ball?





B… at the start the total energy equaled the B… at the start the total energy equaled the gravitational potential, so if the ball only gravitational potential, so if the ball only went ½ as high then only ½ the total was went ½ as high then only ½ the total was transformed… the other ½ was transformed transformed… the other ½ was transformed into thermal energy.into thermal energy.

3.3. Energy is created as the result which Energy is created as the result which activity? activity?

a)a) Burning gasoline in an internal Burning gasoline in an internal combustion engine. combustion engine.

b)b) Damming a river for hydroelectric Damming a river for hydroelectric power. power.


d)d) Energy can only be transformed, not Energy can only be transformed, not created. created.

3.3. Energy is created as the result which activity? Energy is created as the result which activity?

a)a) Burning gasoline in an internal combustion engine. Burning gasoline in an internal combustion engine.

b)b) Damming a river for hydroelectric power. Damming a river for hydroelectric power.


d)d) Energy can only be transformed, not created. Energy can only be transformed, not created.

D… Energy cannot be created or destroyed, it can D… Energy cannot be created or destroyed, it can only be stored or transferred. Total energy only be stored or transferred. Total energy remains constant, but different amounts can be remains constant, but different amounts can be transferred between different storage means transferred between different storage means like… thermal gravitational potential, kinetic, like… thermal gravitational potential, kinetic, electric potential, chemical potential, etc…electric potential, chemical potential, etc…

4.4. Aluminum was once used as the wires in home construction. Aluminum was once used as the wires in home construction. Recently, it was changed to copper wires. Which of the Recently, it was changed to copper wires. Which of the following statements following statements BESTBEST account for why aluminum was account for why aluminum was replaced with copper? replaced with copper?

a)a) When electrical energy is passed through a copper wire, When electrical energy is passed through a copper wire, less of the energy removes copper atoms from the wire. less of the energy removes copper atoms from the wire.

b)b) The electrical energy that a copper wire can transfer is The electrical energy that a copper wire can transfer is less than less than an aluminum wire. an aluminum wire.

c)c) As a byproduct of transmission, more electrical energy is As a byproduct of transmission, more electrical energy is transformed to wasted thermal energy in aluminum wire transformed to wasted thermal energy in aluminum wire than in copper than in copper

d)d) The electrical energy that passes through an aluminum The electrical energy that passes through an aluminum wire cannot be directed as well as the energy passing wire cannot be directed as well as the energy passing through copper. through copper.

4.4. Aluminum was once used as the wires in home construction. Recently, it was Aluminum was once used as the wires in home construction. Recently, it was changed to copper wires. Which of the following statements changed to copper wires. Which of the following statements BESTBEST account account for why aluminum was replaced with copper? for why aluminum was replaced with copper?

a)a) When electrical energy is passed through a copper wire, less of the When electrical energy is passed through a copper wire, less of the energy removes copper atoms from the wire. energy removes copper atoms from the wire.

b)b) The electrical energy that a copper wire can transfer is less than The electrical energy that a copper wire can transfer is less than an aluminum wire. an aluminum wire.

c)c) As a byproduct of transmission, more electrical energy is transformed As a byproduct of transmission, more electrical energy is transformed to wasted thermal energy in aluminum wire than in copper to wasted thermal energy in aluminum wire than in copper

d)d) The electrical energy that passes through an aluminum wire cannot be The electrical energy that passes through an aluminum wire cannot be directed as well as the energy passing through copper. directed as well as the energy passing through copper.

C… In any process or activity, some C… In any process or activity, some energy is lost as thermal energy. To energy is lost as thermal energy. To increase efficiency, we want to increase efficiency, we want to minimize thermal losses.minimize thermal losses.


a)a) voltages can be easily increased and decreased voltages can be easily increased and decreased within the circuit allowing for lower energy within the circuit allowing for lower energy losses during transmission. losses during transmission.

b)b) voltages change direction several times a voltages change direction several times a second to generate electrical charge more second to generate electrical charge more rapidly. rapidly.

c)c) rapid current changes regulate the ease at rapid current changes regulate the ease at which electricity passes through the circuit. which electricity passes through the circuit.

d)d) current most often is high to prevent energy current most often is high to prevent energy losses during transmission, but can be low to losses during transmission, but can be low to decrease the voltage in the circuit. decrease the voltage in the circuit.


a)a) voltages can be easily increased and decreased within the voltages can be easily increased and decreased within the circuit allowing for lower energy losses during transmission. circuit allowing for lower energy losses during transmission.

b)b) voltages change direction several times a second to generate voltages change direction several times a second to generate electrical charge more rapidly. electrical charge more rapidly.

c)c) rapid current changes regulate the ease at which electricity rapid current changes regulate the ease at which electricity passes through the circuit. passes through the circuit.

d)d) current most often is high to prevent energy losses during current most often is high to prevent energy losses during transmission, but can be low to decrease the voltage in the transmission, but can be low to decrease the voltage in the circuit. circuit.

A… In any process or activity, some energy A… In any process or activity, some energy is lost as thermal energy. To increase is lost as thermal energy. To increase efficiency, we want to minimize thermal efficiency, we want to minimize thermal losses.losses.

6.6. Which of the following describes how a dam Which of the following describes how a dam creates electricity? creates electricity?

a)a) Water is heated up and creates steam to turn Water is heated up and creates steam to turn the generator to create electricity. the generator to create electricity.

b)b) Gravitational potential energy transfers to Gravitational potential energy transfers to kinetic energy which turns a generator. kinetic energy which turns a generator.

c)c) Electrons are removed from the water as it Electrons are removed from the water as it passes and creates electricity. passes and creates electricity.

d)d) Water flows over wires in the dam which Water flows over wires in the dam which creates current from the water.creates current from the water.

6.6. Which of the following describes how a dam creates electricity? Which of the following describes how a dam creates electricity?

a)a) Water is heated up and creates steam to turn the generator to create electricity. Water is heated up and creates steam to turn the generator to create electricity.

b)b) Gravitational potential energy transfers to kinetic energy which turns a generatorGravitational potential energy transfers to kinetic energy which turns a generator. .

c)c) Electrons are removed from the water as it passes and creates electricity. Electrons are removed from the water as it passes and creates electricity.

d)d) Water flows over wires in the dam which creates current from the water.Water flows over wires in the dam which creates current from the water.

B… B… The vast majority of electricity we use is from generators. The vast majority of electricity we use is from generators. Generators produce electricity by rotating a wire Generators produce electricity by rotating a wire (electrons) through a magnetic field. A generator can be (electrons) through a magnetic field. A generator can be turned many ways… primarily we use steam pressure turned many ways… primarily we use steam pressure (like steam shooting out of tea-kettle) or moving water to (like steam shooting out of tea-kettle) or moving water to turn a turbine (like a windmill or waterwheel). Our turn a turbine (like a windmill or waterwheel). Our powerplants use natural gas, nuclear powerplants use natural gas, nuclear fissionfission, coal and oil , coal and oil to create steam to turn a turbine. Dams convert the to create steam to turn a turbine. Dams convert the gravitational energy stored in the water behind the dam gravitational energy stored in the water behind the dam into kinetic energy of moving water, as moving water into kinetic energy of moving water, as moving water turns the turbine which turns the generator.turns the turbine which turns the generator.

7.7. A hammer strikes a nail and drives the nail into A hammer strikes a nail and drives the nail into a block of wood. If the action force is the a block of wood. If the action force is the hammer striking the nail, the reaction force is hammer striking the nail, the reaction force is

a)a) the nail striking the wood with an equal and the nail striking the wood with an equal and opposite force. opposite force.

b)b) the nail striking the hammer with an equal the nail striking the hammer with an equal and opposite force. and opposite force.

c)c) the wood striking the hammer with an equal the wood striking the hammer with an equal and opposite force. and opposite force.

d)d) the wood striking the nail with an equal and the wood striking the nail with an equal and opposite force. opposite force.

7.7. A hammer strikes a nail and drives the nail into a block of A hammer strikes a nail and drives the nail into a block of wood. If the action force is the hammer striking the nail, the wood. If the action force is the hammer striking the nail, the reaction force is reaction force is

a)a) the nail striking the wood with an equal and opposite force. the nail striking the wood with an equal and opposite force.

b)b) the nail striking the hammer with an equal and opposite the nail striking the hammer with an equal and opposite force. force.

c)c) the wood striking the hammer with an equal and opposite the wood striking the hammer with an equal and opposite force. force.

d)d) the wood striking the nail with an equal and opposite force.the wood striking the nail with an equal and opposite force.

B… Newton’s 3B… Newton’s 3rdrd Law, for every action, there is Law, for every action, there is an equal and opposite reaction. If you push an equal and opposite reaction. If you push or pull (apply force) to something (anything), or pull (apply force) to something (anything), that something will push or pull on you in that something will push or pull on you in the opposite direction.the opposite direction.

8.8.Which of the following would Which of the following would supply the greatest acceleration supply the greatest acceleration when applied to a 10 kg mass? when applied to a 10 kg mass?

a)a)5N 5N

b)b)10N 10N

c)c)15N 15N

d)d)20N20N

8.8. Which of the following would supply the greatest acceleration Which of the following would supply the greatest acceleration when applied to a 10 kg mass? when applied to a 10 kg mass?

a)a) 5N 5N

b)b) 10N 10N

c)c) 15N 15N

d)d) 20N20N

D… Newton’s 2D… Newton’s 2ndnd Law simply stated Force equals Law simply stated Force equals mass times acceleration. If force increases, mass times acceleration. If force increases, acceleration increase. If mass increases, acceleration increase. If mass increases, acceleration decreases. Force is measured in acceleration decreases. Force is measured in Newtons (N), so 20N is the greatest force Newtons (N), so 20N is the greatest force giving the greatest acceleration. giving the greatest acceleration.


A cart is being pulled North across a A cart is being pulled North across a carpeted floor. Which direction is the carpeted floor. Which direction is the force of friction acting?force of friction acting?

a)a)North North

b)b)South South

c)c) East East

d)d)West West


A cart is being pulled North across a carpeted floor. Which direction is the force of A cart is being pulled North across a carpeted floor. Which direction is the force of friction acting?friction acting?

a)a) North North

b)b) South South

c)c) East East

d)d) West West

B… Friction always opposes the B… Friction always opposes the applied force, so if a force is applied force, so if a force is pulling the block north, friction pulling the block north, friction would be pointing south. would be pointing south.

10.10.You have created a track out of cardboard for a You have created a track out of cardboard for a marble to travel down. In order for the marble to marble to travel down. In order for the marble to complete the track, why does the first hill have to be complete the track, why does the first hill have to be the highest? the highest?

a)a) The friction caused by the track resists the The friction caused by the track resists the motion of the marble. motion of the marble.

b)b) The friction caused by the track increases the The friction caused by the track increases the motion of the marble. motion of the marble.

c)c) Gravity is pulling down on the marble causing it Gravity is pulling down on the marble causing it to slow down. to slow down.

d)d) Gravity is pulling down on the marble causing it Gravity is pulling down on the marble causing it to speed up. to speed up.

10.10. You have created a track out of cardboard for a marble to travel You have created a track out of cardboard for a marble to travel down. In order for the marble to complete the track, why does the down. In order for the marble to complete the track, why does the first hill have to be the highest? first hill have to be the highest?

a)a) The friction caused by the track resists the motion of the marble. The friction caused by the track resists the motion of the marble.

b)b) The friction caused by the track increases the motion of the The friction caused by the track increases the motion of the marble. marble.

c)c) Gravity is pulling down on the marble causing it to slow down. Gravity is pulling down on the marble causing it to slow down.

d)d) Gravity is pulling down on the marble causing it to speed up. Gravity is pulling down on the marble causing it to speed up.

A… Friction would oppose the motion caused by the force of A… Friction would oppose the motion caused by the force of gravity this causes some of the gravitational potential gravity this causes some of the gravitational potential energy to be lost as thermal energy (like rubbing your energy to be lost as thermal energy (like rubbing your hands together). The marble now doesn’t have enough hands together). The marble now doesn’t have enough energy to make it to the same height, so the 2energy to make it to the same height, so the 2ndnd hill needs hill needs to be lower. to be lower.

Questions?Questions?

Class Handouts and Homework

Energy

X

Word List

Capacity for change


Store it

Transfer it

Kinetic

Potential

Position

Elastic

Gravitational

Chemical

Spring

Food

Snowboarder

Objects in motion

Battery

Sun

Radiation

Work

Heat

Waves light

Force

Distance

Friction

Thermal energy

Vibrating atoms and molecules

1.1. PaperclipPaperclipa)a) Open the paperclip into a “V”Open the paperclip into a “V”

b)b) Touch the “V” to your upper lip. How does Touch the “V” to your upper lip. How does it feel? Record observation: it feel? Record observation: ____________________________________________________________________

c)c) Open and close (bend) the paperclip Open and close (bend) the paperclip rapidly at least 10 times and then rapidly at least 10 times and then immediately touch it to your lip. Record immediately touch it to your lip. Record observation: observation: ____________________________________________________________________

d)d) Touch the “V” to your lip again. Record Touch the “V” to your lip again. Record observation: observation: ____________________________________________________________________

e)e) Use the pie charts below to show how the Use the pie charts below to show how the energy was stored and transferred.energy was stored and transferred.

2.2. Spring CartSpring Carta)a) Compress the spring into the cartCompress the spring into the cart

b)b) Place the spring end of the cart against an Place the spring end of the cart against an immoveable object and release spring immoveable object and release spring

c)c) Record observations: Record observations: ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

d)d) Use the pie charts below to show how the Use the pie charts below to show how the energy was stored and transferred. energy was stored and transferred.

3.3. PendulumPenduluma)a) Pull the “bob” back about 30 degrees and Pull the “bob” back about 30 degrees and

release.release.

b)b) Observe the motion for 10 cycles. Observe the motion for 10 cycles.

c)c) Where does the “bob have the most kinetic Where does the “bob have the most kinetic energy? __________________________________energy? __________________________________

d)d) Where does the “bob” have the most Where does the “bob” have the most potential energy? potential energy? ____________________________________________________________________

e)e) What happens to the speed of the “bob” What happens to the speed of the “bob” over time? over time? ____________________________________________________________________

f)f) Is there friction? What would happen if Is there friction? What would happen if there were no friction? there were no friction? ____________________________________________________________________

g)g) Use the pie charts below to show how the Use the pie charts below to show how the energy was stored and transferred.energy was stored and transferred.

4.4. Solar Panel and MotorSolar Panel and Motora)a) Turn on the light and move the solar panel Turn on the light and move the solar panel

toward the light.toward the light.

b)b) Record observations: Record observations: ____________________________________________________________________

c)c) What happens as the panel is moved closer to What happens as the panel is moved closer to the light? __________________________________the light? __________________________________

d)d) Does all of the energy from the light reach Does all of the energy from the light reach the solar panel? Why or why not? the solar panel? Why or why not? ____________________________________________________________________

e)e) Use the pie charts below to show how the Use the pie charts below to show how the energy was stored and transferred. energy was stored and transferred.

f)f) Why is the first pie chart bigger? Why is the first pie chart bigger? ____________________________________________________________________

2012 PVHS NHSPE Review Science Physics Part 1… Energy.

Documents

Transcript of 2012 PVHS NHSPE Review Science Physics Part 1… Energy.