Final Review Questions for Integrated Science
Work, Power, Simple Machines, Kinetic Energy, Potential
Energy and Law of Conservation of Energy
1. Work is
a. the energy transferred when a force causes motion in the direction of the force
b. A disturbance that transmits energy
c. Stored energy
d. Rate at which energy is applied to a body
2. Power is
a. the energy transferred when a force causes motion in the direction of the force
b. A disturbance that transmits energy
c. Stored energy
d. Rate at which energy is applied to a body
3. What are the units used for work?
a. Watts b. meters
c. seconds
d. Joules
e. Newtons
4. What are the units for Power?
a. Watts b. meters
c. seconds
d. Joules
e. Newtons
5. A man pushes on a box with a force of 200 N over a distance of 5 m. Find the work done by the
man.
a. 1000 N
b. 100 J
c. 1000 J
d. 40 W
e. 20 W
6. In problem 5, if the man did the work in 10 s, what was the power produced by the man?
a. 1000 N
b. 100 W
c. 1000 J
d. 40 W
e. 20 W
7. A waitress carries a tray of food 40 m from one end of the room to the other. How much work
did the waitress do on the tray of food?
a. none
b. 0 J
c. 1000 J
d. work is done
8. Paul steps off the top step of a stairwell his left foot is on the top step and his right foot is in the
air. What forces do work on Paul?
a. gravity
b. normal
c. a + b
d. none
9. A student drops a water from the second floor window which is 20 m above the ground. The
water balloon has a weight of 5N. How much work is done on the balloon by the force of
gravity. 100 J = W
10. Joe dragged Eric across the rug in the library at a constant speed. What are the two forces that
did work on Eric?
a. gravity b. friction on Eric
c. applied by Joe
d. b + c
e. none
11. Both Matt and Nick lift a bucket of water with a weight of 50 N a distance of 10 m. Matt did
it in 5 s and Nick lifted the bucket in 8 seconds.
a. Who did more work?
a. Matt
b. Nick
b. Who was more powerful?
a. Matt
b. Nick
12. Which of the following is a complex simple machine?
a. pulley
b. ramp
c. wedge
d. screw
e. elevator
13. List three simple machines?
Ramp, wedge, screw
14. What is the purpose of a machine?
a. Lessen work
b. Lessen force
c. Both a and b
15. T or F : A machine can do more work than you do to it.
F
16. What is mechanical advantage?
The factor by which effort force is reduced by a machine
17. Define efficiency for a machine.
Work out of a machine/work put into the machine
18. Piano movers are moving a piano into a house on First Street. The piano has a weight of 1000 N.
They use a ramp that is 10 m long to raise the piano 2 m. They push with a force of 500 N on the
piano along the entire ramp to get it into the house. Find the following values.
a. Work in = 5000 J
b. work out = 2000 J
c. Mechanical advantage = 2
d. efficiency = 0.4
19. Two child are playing on a see saw. Each of the children has a weight of 400 N, and they both
are sitting 2.5 m from the fulcrum of the see saw. Find the following values.
a. Work in = 1000 J
b. work out = 1000J
c. Mechanical advantage = 1
d. efficiency = 1
20. Kinetic energy is energy of:
Motion
21. Define Gravitational Potential Energy.
The energy a body has due to the position above the ground.
22. Define the conservation of Energy.
NRG can be transformed from one form to another but can not be created or destroyed. The
total Mechanical NRG of a system will always be constant.
23. What is the equation for kinetic NRG?
KE = ½ mv2
24. T or f: If the mass of an object changes then the kinetic energy will also change.
T
25. What is the equation for gravitational potential NRG?
PE = mgh
26. What are the units used for kinetic NRG?
J
27. What are the units used for potential NRG?
J
28. What the units for mass?
Kg
29. What is an example of non-mechanical NRG?
Heat, sound
30. A bowling ball rolling down the alley has what type of NRG?
Kinetic NRG
31. Jeff has a mass of 50 kg and is standing 20 m above the ground.
a. Find his gravitational potential energy.
10000 J
b. Jeff is now standing on the ground. Find his gravitational potential energy.
0J
c. Find the change in gravitational potential energy for Jeff if he started at 20 m above the
ground and ended at ground level.
10000 J
32. Jason is running along the street. He has a mass of 45 kg.
a. Find the KE Jason has if he is traveling at 2 m/s.
KE = 90 J
b. Find the KE Jason has if he is now traveling at 4 m/s.
KE = 360 J
c. Find the change in KE for Jason.
KE = 270 J
d. How much was the increase in speed for Jason?
Two times
three times
four times
33. If a rock is sitting on the ground (not moving and with no height) what type of energy does it
possess? PE
34. For a closed system, what does the Law of conservation of NRG say for KE+PE?
The sum will be equal at all points of the motion.
35. Complete the chart for the roller coaster cart at each of the points.
A
D
B
h
C
E
Position
A
h (m)
100
PE (J)
800000
KE (J)
3000
TME (J)
803000
B
50
400000
403000
803000
C
20
160000
643000
803000
400000
403000
803000
0
803000
803000
D
E
50
0
a. What is constant throughout the trip?
The TME
b. At which point is the cart moving the fastest?
E
c. Is the cart moving at point A? Explain how you know using the data in the table.
Yes, the cart has KE at A so it is moving at that point.
d. How are points B and D related to each other? What is the same for each point? What is
different for each point?
They are at the same height on the coaster. They have the same speed, the same PE and the same KE.
They are moving in different directions.