Download Online Self-Assessment Quiz – Work and Energy

Online Self-Assessment Quiz – Work and Energy
1. What is your name? Mrs. Bridgewater 
2. TRUE - When work is done on an object, the energy of the object changes.
3. How much work does the force of gravity do on a 5.45-kg bowling ball that falls a distance of 0.755 m?
a. 4.11 J
b. 71.2 J
c. 262 zJ
d. 40.3 J
4. Energy is defined as ____________________.
a. The effort required to perform work
b. The ability of an object to produce change in the environment or itself
c. Motion
d. Power
5. The book says the work = change in kinetic energy. Let’s say you do work to raise the book higher.
Write a few sentences about how the work you do might change the kinetic energy of the book and
about how the work you do might change the potential energy of the book. Think about whether you
agree, disagree or might modify the book’s statement.
The book is put in motion so the KE increases as it rises but then it slows down to a stop. So the change
is in the potential gravitational energy. And that’s what the work did
6. If you use a ramp instead of puling an object straight up with a rope, does it change the amount of work
you have to do?
a. No, it changes the amount of force required
b. Yes, it reduces the amount of work
c. Yes, it increases the amount of work
d. No, it changes the efficiency
7. A student lifts a box of books that weighs 215 N. The box is lifted 1.75 m. How much work did the
student do on the box?4
a. 38.4 J
b. 123 J
c. 225 J
d. 376 J
8. In #7 above, he uses a frictionless ramp (suspend disbelief) to push the books to the same final height. If
the ramp is 3.5 m long, how much force did he have to exert?
a. 215 N
b. 107.5 N
c. 21.5 N
d. 11.25 N
9. If a force is exerted on an object opposite to its motion, the kinetic energy of the object ________
a. Is zero
b. Decreases
c. Increases
d. Remains the same
10. The work-energy theorem states that _________________.
a. When a machine works at 100 percent efficiency, the energy of the system remains constant
b. Effort is required to resist a change in the energy of a system
c. When work is done on an object, a change in kinetic energy results
d. When work is done at a rate of one joule per second, the power produced is on watt
11. Joey pushes a 5 kg box along a floor with a force of 15 N. He does this for 5 seconds and the box moves
7 meters. How much work does he do on the box?
a. Zero work
b. 35 J
c. 105 J
d. 75 J
12. Regarding your answer to #11, explain your answer.
Joey exerts a force on the box that increases the KE of the box.
13. A NASCAR crew pushes a race care off the racetrack at constant velocity. The car’s mass is 7400 kg and
the crew pushes with a force of 1100 N for 50 meters. How much work do they do on the car? (13, 14,
and 15 go together)
a. They do no work on the car
b. The do 375000 J of work
c. The do 55000 J of work
14. How much work does the force of gravity do on the car?
a. It does no work on the car
b. It does 37400 J of work
c. It does 75000 J of work
15. What is the new work done on the car by all forces acting on it?
a. Zero net work
b. 375000 J
c. 55000 J
d. 75000 J