Download Answers

Unit 3 – Energy Study Guide
1. Energy is the ability to do work.
2. _______ is stored in a car battery.
a. Potential energy
b. Kinetic energy
c. Chemical energy
d. Both a and c
3. Potential Energy is the energy of position, shape or composition.
4. Kinetic energy is the energy of motion.
5. Energy is measured in Joules. (it’s the same unit as work)
6. Mechanical energy is the sum of kinetic and Potential energy.
7. The gravitational potential energy of 24 N turtle, sitting on a post 4 meters above the ground is
a. 96 Joules
b. 96 Watts
c. 6 Amps
d. 6 pounds
8. A person falling from an airplane has
a. Mechanical energy
Remember that mechanical energy is the
b. Potential energy
sum of Potential AND kinetic and as
c. Kinetic energy
you’re falling, you have both so you
d. All of the above
have mechanical energy as well.
9. Energy transformation is when energy changes from one form to another and energy transfer is when
energy moves from one body to another.
10. Gravitational potential energy is calculated by
a. Multiplying weight times height
b. Multiplying mass times height
c. Multiplying mass times velocity
d. None of the above
11. The kinetic energy of a 1 Kg soccer ball traveling at 10 m/s is
a. 50 J
b. 100 J
c. 10 J
d. None of the above
12. A 1000 Kg car moving at 20 m/s has more kinetic energy than a 2000 Kg truck moving at 10 m/s, true or
false? True! The faster something is moving, the more kinetic energy it has. Since the 1000 Kg is
traveling with more velocity it has more kinetic energy.
13. Use the following data table to describe the energy in the diagram. Please read the blurb on the side to
help you figure out what’s going on?
Energy form present in
Energy transfer or
Step
Description of Action
step
Transformation
A to B
Car hits hammer
Mechanical
Transfer
B to C
Hammer hits buzzer
Mechanical
Transfer
C to D
Buzzer scares rabbit
Sound
transformation
D to E
Rabbit runs towards hole
Mechanical
transformation
E to F
Rabbit pulls string
Mechanical
Transfer
F to G
String sets off gun
G to H
Bullet hits can
Thermal/Sound/Chemical Transformation
(fire in gun)
Mechanical
Transformation
H to I
Water from can drips into aquarium
Mechanical
Transfer
I to J
Raises floating cork
Mechanical
Transfer
14. Explain the energy in the pendulum shown. Draw a picture to help explain your description.
At its highest point, the pendulum has all potential energy. As the bob (ball)
is released the potential energy changes into kinetic. Halfway down, the bob
has half potential energy and half kinetic, but the mechanical energy hasn’t
changed. At its lowest point, the pendulum has 100% kinetic energy. The
pendulum begins to move back up, and the energy begins to switch between
Potential and Kinetic energies again. Halfway up, the bob has 50% PE and
50% KE. At its highest point on the other side, the energy is 100% PE.