Energy Review #H1 (PE vs. KE )

Potential and Kinetic Energy

Multiple Choice

Energy is _______.

• a type of element

• the ability to do work or cause change

• a physics calculation

Multiple Choice

The law of conservation of energy means ________________________

• Energy CAN be created and destroyed or transformed
• Energy can be used up or transformed
• Energy CANNOT be created or destroyed, only transformed
• Energy cannot be transformed

What Is Energy?

• Energy is the ability to do work or cause change.
• Everything that happens in the world uses energy!
• Most of the time we can’t see energy, but it is

everywhere around us!

• Energy is NEVER created or destroyed, it can only be

STORED or TRANSFERRED.

• This is called the L.O.C.O.E. (Law of Conservation of

Energy)

Batteries store energy!

This car
uses a
lot of
energy

We get
our
energy
from
FOOD!

Even this
sleeping
puppy is
using
stored
energy.

Remember:

ALL matter is made up
of particles.

The particles NEVER
stop moving.

On the atomic level,
all matter has kinetic
energy.

All 7 Forms of
Energy can be
classified as:

Potential
Energy
(stored)

Kinetic
Energy
(in use)

Potential Energy is…

• The energy stored in an object.
• "Potential" simply means the energy has the ability

to do something useful later on.

Examples of Potential Energy:

A stretched rubber band..

Water at the top of a waterfall..

Yo–Yo held in your hand..

A drawn Bow and Arrow…

• The higher an object, the more potential

energy.

• The more mass an object has, the more

potential energy it has.

Formulas:
PE = Weight (w) x Height (h)

PE = Mass (m) x Gravity (g) x Height (h)

Measured in the unit of Joules (J)

Potential Energy

Which object has more potential energy?

A

B

Practice Question

ANSWER

A

This brick has more mass than the feather;

therefore more potential energy!

If you drop an object from the top of one of these
three things, where will be the most potential energy?

A

B

C

Practice Question

ANSWER

• The higher the

object, the more
potential energy!

A

Multiple Choice

__________ energy is the energy due to an object's position or condition

• Potential
• Kinetic
• None of the above 
• All of the above 

Multiple Choice

Potential energy depends on the ________ and ________ of the object.

• Height and mass or weight

• Friction and movement

• Mass and Movement

• Height and Friction

Multiple Choice

Energy is measured in which unit?

• grams

• meters

• inches

• Joules

Multiple Choice

At which point is potential energy greatest?

• W
• X
• Y
• Z

Multiple Choice

What would be the potential energy of ball A if it weighs 10N and is 15 meters off the ground?

• 1.5Nm or 1.5J

• 5Nm or 5J

• 25 Nm OR 25 J

• 150 Nm or 150 J

Multiple Choice

What would be the potential energy of ball E if it has a mass of 5kg and is 2 meters off the ground? (g= 9.8 m/s²)

• 10J

• 98 J

• 16.8 J

• 27 J

Potential Energy Converted to

Kinetic Energy…

• When stored energy begins to move, the

object now transfers from potential
energy into kinetic energy.

Stored potential energy in the food is converted to mechanical energy when we move.

Kinetic Energy Is…

• The energy of a moving object.
• "Kinetic" means movement.
• When stored energy is being used up, it is making things

move or happen.

Examples of Kinetic Energy:

• The faster the object

moves, the more kinetic energy is produced.

• The greater the mass and velocity/speed of an

object, the more kinetic energy there will be.

Formulas:
KE = mass x (velocity)2 or ½ mv2

2

When these objects move at the same

speed, which will have more kinetic energy?

Practice Question

18 Wheeler Electric Car

ANSWER

The semi- truck has more mass;
therefore, more kinetic energy!

Multiple Choice

Energy due to motion is ____________ energy. 

• Potential 
• Energy
• Kinetic
• Friction

Multiple Choice

Which is the best example that something has kinetic energy?

• a. a car parked on a steep hill 
• b. a tennis ball rolling across the court
• c. a picture hanging on the wall 
• d. a piece of coal before it's burned 

Multiple Choice

The faster an object moves, the ________ kinetic energy it has. 

• more
• less
• none of the above
• all of the above 

Multiple Choice

What is happening to the energy of the girl from point A to point B

• kinetic changes to potential
• potential changes to kinetic
• energy is lost
• energy is gained

Multiple Choice

Calculate the kinetic energy of the 10kg object in this picture?

• 10 J

• 100 J

• 500 J

• 1000 J

A water bottle is knocked off a table.

When does the bottle have the MOST kinetic energy?

A. At the top of the fall.
B. In the middle of the fall.
C. At the bottom of the fall,
right before it hits the floor.

Practice Question

• C. At the bottom of the fall.

• It has the most kinetic energy when its movement

and speed are greatest, which is at the bottom of

the fall right before it hits the ground.

• When an object has the LEAST potential energy is

when it has the MOST kinetic energy.

Practice Question
At what point does the car on this roller coaster have the MOST potential energy?

ANSWER

•Point B : At the top of the
tallest hill.

•The HIGHER the train is
lifted by the motor, the
MORE potential energy is
produced.

•At the top of the hill the
train has a huge amount of
potential energy, but it has
very little kinetic energy.

At what point does the train on this roller coaster have the MOST kinetic energy?

Practice Question

• As the car accelerates

down the hill the potential energy is converted into kinetic energy.

• There is very little
potential energy at the
bottom of the hill, but
there is a great amount
of kinetic energy.

Answer:Point C (moving towards the bottom of
the tallest hill)

Multiple Choice

^{Which point has the greatest kinetic energy?}

• W
• X
• Y
• Z

Multiple Choice

Which bowling ball has LESS kinetic energy

• 8 m/s
• 10 m/s
• they have the same amount of enery
• none of these

Multiple Choice

Which point has greatest kinetic energy?

• A
• B
• C
• none

Summary Notes

• All energy is divided into two types: potential

and kinetic.

• Potential Energy: The energy stored in an object.

• Kinetic Energy: The energy of a moving object.

• Energy is never created or destroyed. It is always

stored or transferred.

• An object has the MOST kinetic energy when

its mass and movement is the GREATEST.

• An object has the MOST potential energy

when it is heavier and higher off the ground.

• The TOTAL energy remains the SAME in the

entire system, it just shifts from PE to KE and back constantly.

Pendulum Example: https://www.mathsisfun.com/physics/pendulum.html

• The TOTAL energy remains the SAME in the entire system, it just shifts from PE

to KE and back constantly.

Practice

There are 6 TOTAL joules of energy in this pendulum system. The energy amounts are listed for position 1, what would be the amounts for positions 2 and 3?

Multiple Choice

Why can't the skater reach the same point where he was released when he goes up the other side of the ramp?

• because he is heavy

• because his mass is slowing him down

• because he gets tired

• because friction and gravity are slowing him down

Multiple Choice

When a pendulum swings, at which point is kinetic energy highest?

• 1
• 2
• 3
• 4

Multiple Choice

When a pendulum swings, at which point is potential energy at its greatest? (assume there is no friction)

• 1 and 5
• 2 and 4
• 3 
• 4 and 5

Multiple Choice

Calculate the KE of a runner that has a mass of 80 kg and is running at a velocity of 8 m/s

• 5120 J
• 320 J
• 640 J
• 2560 J

Multiple Choice

A 60 kg go cart is travelling at a constant speed of 7 m/s. What is its kinetic energy in J?

• 1470 J

• 2100 J

• 1.47 J

• 21 J

Multiple Choice

A 60N baby bear has climbed 5 meters high in a tree. What is its potential energy in J?

• 2,940 J

• 300 J

• 750 J

• 9,000 J

Multiple Choice

How much kinetic energy does a person of mass 50kg running at 3m/s have?

• 225,000 J
• 225 J
• 75,000 J
• 75 J

Multiple Choice

How much potential energy does a 50N person have when they are sitting on a deck 3 meters in the air?

• 50 J

• 490 J

• 25 J

• 150J

Multiple Choice

Two objects with the same mass (m) are placed on 2 shelves at different heights. Which object contains more potential energy?

• The object on the higher shelf.

• The object on the lower shelf.

• Both objects have the same amount of potential energy.

• Neither object has any energy because they are not moving.