Name: ____________________________
Date: __________
Block: _______
Unit 4 Review
1. Define the following scientific terms.
a. Work: __________________________________________________________________
________________________________________________________________________
b. Power: __________________________________________________________________
________________________________________________________________________
c. Energy: _________________________________________________________________
________________________________________________________________________
d. Gravitational Potential Energy: ______________________________________________
________________________________________________________________________
e. Kinetic Energy: ___________________________________________________________
f.
Law of Conservation of Energy: ______________________________________________
________________________________________________________________________
2. State either “yes” or “no” if scientific work is being done on an object in the following scenarios.
a. A horse pulling a cart down the road.
________
b. A man lifting a box off the floor.
________
c. A student pushing on the wall of the school.
________
d. A hockey puck sliding across the ice at a constant speed.
________
e. A student carrying a book down the hallway.
________
3. Jonathan is working on a small gas motor in the small gas engines class. He works on the engine
and increase the power it can produce.
a. How will Jonathan’s modifications to the engine affect the time it takes for the engine to
complete work? __________________________________________________________
b. How will Jonathan’s modifications to the engine affect the amount of work the engine
can do in a specific amount of time? __________________________________________
4.
What is the Work-Energy Theorem? ________________________________________________
______________________________________________________________________________
5. How much work does it take to lift an object and increase its potential energy by 50 J?
_______________________________________________________________________
Name: ____________________________
Date: __________
Block: _______
6. A car has 100 J of kinetic energy when moving down the road. The drive applies the brakes and
reduces the kinetic energy of the car to 30 J.
a. How much work have the brakes done on the car? ______________________________
b. Is the work positive or negative? _____________________________________________
7. What factors about a basketball affect the amount of potential energy it has? _______________
______________________________________________________________________________
8. What factors about a basketball affect the amount of kinetic energy it has? ________________
______________________________________________________________________________
9. Answer the following questions based on the equations learned in Unit 4:
W F d
P
W
t
PE  m g h
1
KE   m  v 2
2
a. When the height of an object triples, the Potential Energy of the object __________.
b. When the speed of a car doubles, its Kinetic Energy __________________________.
c. If Mike does the same work as Jonah but in a fourth of the time, how much power does
Mike generate compared to Jonah? _______________________________________.
d. If Sarah pushes on a shopping cart with twice the force and for twice the distance, she
does ___________________ work.
10. An archer shoots an arrow up into the air with an initial kinetic energy of 60 J of work.
a. When the arrow reaches the top of the path, how much KE will it have?
______
b. When the arrow reaches the top of the path, how much PE will it have?
______
c. If there is no air resistance, when the arrow comes back down to the archer, how much
KE will it have?
______
d. If there is air resistance, when the arrow comes back down to the archer, how much KE
will it have?
e. No matter where the arrow is, how much total energy will it have?
11. Fill in the PE and KE for each blank in the diagrams below.
______
______
Name: ____________________________
Date: __________
Block: _______
Use the equations provided to answer the following questions.
W F d
P
W
t
PE  m g h
1
KE   m  v 2
2
W  E
Ei  E f
12. A crane lifts a 100 N barrel up into the air 15 m in a time of 20 seconds. How much power did
the crane have to generate to complete the work?
13. A shopper does 500 J of work pushing a shopping cart. If the cart moved a distance of20 meters,
how much force did the shopper place on the cart?
14. A 75 kg runner is jogging down the road at a speed of 5 m/s.
a. How much kinetic energy does the jogger have?
b. If the jogger speeds up to 8 m/s, how much kinetic energy will they have?
c. How much work did the jogger have to do to speed up?
d. If the jogger accelerated over a distance of 20 meters, how much force did their legs
have to generate to create this acceleration?
Name: ____________________________
Date: __________
Block: _______
15. A driver is being reckless and accidently drives off a 20 m tall cliff at a speed of 10 m/s. The
mass of the car is 2000 kg.
a. How much PE does the car initially have at the top of the cliff?
b. How much KE does the car initially have as it drives off the cliff?
c. What is the total energy of the car at the top of the cliff?
d. When the car is still 5 m off the ground before crashing, how much total energy does it
have?
e. How much PE does the car have 5 m off the ground?
f.
How much KE does the car have when it is 5 m off the ground?
g. How fast will the car be moving when it reaches 5 m off the ground?