potential and kinetic energy force, motion, and...

Potential and Kinetic EnergyForce, Motion, and Energy

STUDENT GUIDE

Part I: Types of EnergyWhat is a system?

Energy

A system in science is a group of interacting or interdependentelements forming a complex whole, as in all the factors or variablesin an environment or all the variables that might affect a scienceexperiment. Think of a sÿstem as a set of thinÿts that arerelated. An example of a system is a boy using a slingshot. The y-

handle, the elastic bands, the pocket that holds theprojectile, and the projectile are all parts of the slingshot system.To make theslingshot work, a force is added to the system from theboy's hand pulling back on the elastic bands. All parts of the slingshot system work together tolaunch an object into the air.

What is energy?

Energy is the ability to use force to move an object over a distance or to cause chanÿmatter. Energy iÿs a ÿthat can be measured. Thejoÿ is the unit used to measure energyand is represented by "J." Joule units measure energy just like meters measure distance,degrees measure temperature, or seconds measure time. Joule units can be understood as howmuch energy is needed for change within a system.

In the slingshot system, the boy applies energy to the system by pulling back on the stretchyelastic bands. The applied energy to the slingshot system results in the energy of motion when theboy releases the elastic band.

Types of EnergyIn previous grades, you learned about using different types of energy, for example, mechanical,li ht, sound, .... electrical, and thermal energy. All types of energy can be categorized as one of twobasic types of energy - kinetic energy and ÿrgy.

,L Potential energy is energÿn an object, or energy waiting to happen. Sometimes, potentialenergy is described as graÿtational potential energy because objects have the potential to changetheir positions due to the force of gravity. Sometimes, potential energy is described as chemicalpotential energy, because the energy is stored within the matter itself. Sometimes, potential energyis described as elastic potential energy because it is stretched orÿcompressed within the object.

- Kinetic energy is the energy of motion. Only matter in motion has kinetic energy.

Please continue to the next page of the Student Guide.

ccelerate ,ÿ%.. ÿ Lea rn i ng ÿ ÿoÿ.ÿ.oÿ Aooo,o,.°ÿo ,ÿoom,.ÿ- A,, .,ÿ .oooÿ..d

______________


STUDENT GUIDE

Part I: Types of Energy, continued

Potential Energy Example Kinetic Energy Example

The apples are on the tree highabove the ground. The appleshave the potential to fall to theground. The energy of theapples in this system is storedbecause of their position.

When the apple is in free falldue to the force of gravity,the apple is in motionand has kinetic energy.

Another Apple Example

Potential Energy Kinetic Energy

The apple contains stored energy betweenthe elements and compounds that make upthe apple. The apple has thepotential to provide nutrientsto living organisms when it isbroken down during digestion.The energy in this system isstored within the matter of the apple.

Potential and Kinetic Energy as types of the Total Energy in a System

The living organismthat eats the apple anddigests it to obtain thenutrients neededfor body functions, likegrowth and movement.When the body is inmotion, it has kinetic energy.

All energy can be identified as either potential or kinetic energy. Both potential and kinetic energyare types of energy, are measured using the unit J, and together, make up the total energy of asystem.

. Study the diagram in Part I of your Student Journal that shows potential and kinetic energyexamples.

2. Discuss with a partner why these examples represent potential or kinetic energy.

3. Your teacher will give you a set of cards to cut apart and paste into the chart titled 1. Potentialand Kinetic Energy Pairs within a System. Recycle the paper scraps.

4. Answer Part I questions in your Student Journal.

Complete Part I in your Student Journal.

ccelerate ,. 2

Name:


Date: Group: '/(ÿ(€-"

STUDENT JOURNAL

Part I" Types of Energy

1. Use the information you have learned to fill in the chart below.

• -" K: .ÿ,"ÿ'>.. . "

" " {ÿ!.SÿI#:; U ,'-::::: ........... [ '.

f ÿ:ÿ " -/"ÿ: ÿ\/ I ' IEI [ ................ "®---" ,\

, Think about two pictures that could be added to the chart above for a child swinging on a swing.Describe how the picture of the child on a swing would look when placed under the potential

energy column. ÿ.ÿ C/ÿ !Oÿ iÿ) ÿ L)ÿ ÿ "ÿ 0 ÿt

.

ccelerate%ÿ,LearninÿTM

Describe how the picture of the child on a swing would look when placed under the kineticenergy column.__ÿ ÿ(ÿ,

,j© 2014-2015 Accelerate Learning- All Rights Reserved


STUDENT GUIDE

Part I1: Potential and Kinetic Energy of Pendulums

Have you ever seen a wrecking ball attached to a crane at aconstruction site? Chances are that you have not becausewrecking balls are not used as frequently as they oncewere. Wrecking balls were common sights in the1950s and 1960s, and were used to demolish large buildings.A wrecking ball is like a pendulum. The massive metal ballIs the same as a bob on a pendulum. It can be held in positionby a chain directly above a structure and released in free fall, so it utilizes gravitational potentialenergy and kinetic energy to smash the structure. Another demolition method is to position thewrecking ball to the side of a structure and raise the ball high in the air to utilize gravitationalpotential energy. When released, the kinetic energy of the swinging ball smashes side of thestructure. In this activity, you compare and contrast the potential and kinetic energy of a mini-wrecking ball, or pendulum.

Procedure:

. Place the wood block at the spot labeled "Block Start." Keep the string straight while raising thependulum bob 10 cm above the floor. (Use a meter stick to measure the distance from the floorto the pendulum bob.)

,

3.

Release the pendulum bob.

.

Mark the displaced position of the block with a piece of tape labeled "Block Stop." Measure thedistance between "Block Start" and "Block Stop." Record the measurement on the data tablein your Student Joumal titled Height of Pendulum Bob vs. Distance Traveled by Block.

Leave the piece of tape labeled "Block Start" in place and move on to repeat the rest of theprocess twice. Record your results and calculate the average of the three distances in yourStudent Journal.

.

6.

7.

8.

Repeat the entire process for three trials starting with the pendulum bob height at 20 cm.



Graph the results in your Student Journal and answer the questions for Part II.

Please continue on the next page.

AccelerateLea rn i ng'- ©

3

STUDENT JOURNALPotential and Kinetic Energy

Force, Motion, and Energy

Part I1: Potential and Kinetic Energy of Pendulums

1. Use the table below to collect data from the investigation.

Release Height of Pendulum Bob vs. Distance Traveled by Block

20 cm

40 cm

, Graph the data results usinthese guidelines:

Title:

• Graph only the averages.• Label the x-axis and the

axis.

• Include a title and a legen(for the graph.

Legend:

/

ccelerate, Learning'-

U

© 2014-- 2015 Acoelerate Learning - All Rights Reserved2

5o55

51015202530354045

6065

Potential and Kinetic Energy

STUDENT JOURNAL Force, Motion, and Energyi( .t

Part I1: Potential and Kinetic Energy of Pendulums, continued

3. List the parts of the system that you explored in the actlMty.

4. What happened to the block of wood after the pendulum bob struck it? Explain by stating whattype of energy was demonstrated.

.

°

Which release height of the pendulum bob caused the wood block to move the furthestdistance? ÿ.ÿ t

Which release height of the pendulum bob caused the wood block to move the shortest

distance? "-ÿ'ÿ qJ ÿ(@ÿ ÿ@ ÿ#Jÿ It ÿ+

, Describe the pattern in the data. In other words, how did the changes in the starting height ofthe pendulumbob affect how far the block moved?

--ÿ)ÿ n ÿ-B-ÿ, }dL[J. _ ,ÿ _JJ. ^ f,,ÿ1ÿ /,: u'uJ Ot./# •(r',C,.-- ÿ, v'ÿ ', t'kÿj'{ [ V',ÿ..- ,,ÿ,," ÿL.,'c.--'ÿ ÿ'F

,

gÿ

How does raising the height of the pendulum bob affect its potential energy?

As the pendulum is let go from increasing heights, how is the resulting kinetic energyÿaffected?

What is the evidence?/ÿ\ÿ 0 ÿÿ [ÿ,ÿi Iÿ, ÿ<11ÿ" fÿ ÿ---ÿ ÿ"[ ÿ-ÿ'ÿ5 ÿ'j"

10. Use the constructed graph to predict how far the block could travel if the pendulum bob's

release height is 50 c_mm. ÿ/"[ÿ7ÿ t"[ÿ-4- ÿ,1 ÿS t ÿ[0 /ÿ? C{,ÿ'ÿ /ÿ}'ÿ

II. Explain how the initial height of a wrecking ball is directly related to its ability to demolish a verythick concrete wail. Use the words potential and kinetic energy" r explanation.

G-

© 2014.2015 Accelerate Learning - All Rights Reserved

ccelerate%ÿ,=LearningTM

3

, .............. 7 .....


STUDENT GUIDEPart II1: Compare and Contrast Potential and Kinetic Energy

You have learned that potential energy and kinetic energy make up the total energy within asystem. Compare and contrast these two main types of energy by completing the chart titledCharacteristics of Potential and Kinetic Energy in Part III of your Student Joumal.

1. Your teacher will give you a set of cards to cut apart and paste into the chart.

2. Read all the cards to determine how they show comparison and how they should be pairedwith another card. Paste each related pair under the correct column for Potential or Kinerticenergy

3. Use the completed chart to answer the Part III questions in your Student Journal.

4. Clean your area by placing all paper scraps in the paper recycling bin.

Complete the remaining questions in your Student Journal.

ccelerate ,ÿ 4



Part II1: Compare and Contrast Potential and Kinetic Energy

1. Use the information you have learned to fill in the chart below.

;[

Accelerate%ÿ,,LearningTM © 2014.201ÿ5 Acoeleral.e Learning - All RtghL,ÿ Reserved

4


TEACHER PRINTOUT

Characteristics of Potential and Kinetic Energy

Depends on the surrounding system, becausethe motion of the object is shown by

,ÿomparison to other objects within a system.

Can be transferred from one object to anotherobject within a system, for example: the

of bowling ball can strike and transferenergy of motion to bowling pins.

Cannot be transferred to other objectsbecause the energy is stored within the object, ÿ

for example: the elasticity of a rubber band /cannot transfer to another rubber band. ÿ'o

Measured in joules (J).

Part of the total energy of a system and canr change based on the variables of height,(,ÿ mass or elasticity.

,,,,,

Part of the total energy of a system and can

,,ÿ.ÿnge based on the variables of speed ormass.

The energy stored within the matter of theobject

Measured in joules (J).

An example is: An arrow flying through the airtowards a target.

The energy of moving objects.

An example is: A diver standing at the edge ofthe high dive board.

Depends on the surrounding system, becausestored energy is based on current position asf. compared to usual position, for example, ./ÿ

height or stretch. F

Accelerate%,,LearningTM © 2014 -2015 Accelerate I,.eaming - All Rights Reserved

c9500105

Highlight

c9500105

Highlight

c9500105

Highlight

c9500105

Highlight

c9500105

Highlight

c9500105

Highlight



Part II1: Compare and Contrast Potential and Kinetic Energy, continued

. Define potential energy and then explain what factors, or variables, cause potential energy tochange. <ÿ..ÿy_ ÿ_ plÿ_.ÿ. ÿ\ÿ i I/iÿi)ÿS/ ÿilÿSÿ(gtÿGI

/. Define kinetic energy and then explain what factors, or variables, cause kinetic energy to

change, tpÿO ÿ/ÿ _ ÿ? ÿ ÿ @ÿ Ci, fÿ 0 '\f Vÿi% Oÿÿ(ÿ ÿ ¢ÿdÿ,S,]ÿ,ÿ.S \ÿ9 ÿ ÿ/ÿj)•

, Provide an everyday example of, kinetic energy transfeEring from one object to another object.

. Provide an everyday example of an increase in the total energy of a system due to an increase

inpotential energy. '-½]ÿ:Aÿ'P,- ÿ 0 U) [ÿ

° If you put your backpack in the car and then drive to the mall, is your backpack in motion whencomparing it to the system of the car? Does the backpack have kinetic energy while you are onyour way to the mall? "//'/-/0 /-4d 07/-7ÿ/1 C_ ÿ ¢I-ÿ/ÿ'-ECÿ ÿ::ÿ ÿ_-Czÿ'ÿ

j"

ccelerate ,o,,Learning © 2014 - 2015 Accelerate Learning -AIt IRighL,ÿ Reserved

5



Reflections and Conclusions

. What is energy? e/,ÿ!ÿiiiÿV

. Whatisasystem

3. What are the two types of energy withir system?a

I/ .

4. What is the unit of measure for energy? ÿ.j 0 U"/ÿ

. How are potential and kinetic energy alike?

K, How are potential and kinetic energy different?

o Look at the diagram below. Describe the ball when it demonstrates potential energy. Describe(ÿe ball when it demonstrates kinetic energy. ÿf'ÿ'

, ÿÿ,, ,,ÿ,ÿ

Accelera.te%,.LearningTM

r

© 2014.2015 Acceleral,e Learning - All R|ghL'ÿ Reserved6

potential and kinetic energy force, motion, and...

Documents