Power Practice Problems
1. A crane lifts a load of steel that weighs 9.3 _ 105 N a distance of 100 m. It takes 5
minutes to complete the task.
a. How much work is done by the crane?
b. How much power does the crane produce?
2. A 49 newton rock is lifted 2 meters in 5 seconds.
a. How much work is done?
b. What power is used?
3. A box is pushed across the floor for a distance of 5 meters with a force of 50 newtons
in 5 seconds. What is the power?
4. A woman lifts a 300 newton child a distance of 1.5 meters in 0.75 seconds. What is
her power output in lifting the child?
5. An 190,000 W engine can accelerate from rest to a top speed in 9 s. How much work
did the engine do?
6. Another engine reaches its top speed from rest in 7.5 s. It is able to perform
250,000 J of wok in that time. How much power does this engine have in that
time?
7. If a runner exerts 350 J of work to make 125 W of power, then how long did it
take the runner to do the work?
8. A machine produces 4000 Joules of work in 5 seconds. How much power does the
machine produce?
9. At a tractor pull, one machine has a run that produces 28,000 Joules in 2 seconds.
How many Watts of power did this tractor produce?
10. Jonah des 55J of work when pushing a box across the classroom floor over a time
period of 4s. How much power did Jonah use?
11. Delante pushes a box across the floor 5m with a force of 12N. He pushes the box for
10s. How much power did Delante use to push the box?
12. Quanshe Pushed the same box 5m back across the classroom floor. It takes her 4s,
and she uses a power of 12 W. With what force was she pushing?
13. Kedron was pushing a toy car across the floor with a force of 20N. It took him 10 s
to push the box, and he used a power of 23W. What distance did he push the box
back across the floor?
14. A man does 25J of work on a box that he pushes 10m across the ground in 3s. How
much power does he use?
15. If a Raheim exerts 223J of work to make 72 W of power, then how long did it take
the Raheim to do the work?
16. Jeremy produces 4000 Joules of work in 5 seconds. How much power does he
produce?
17. An 46,000 W super James can accelerate from rest to a top speed in 3 s. How much
work did super James do?
18. Parker was pushing a toy car across the floor with a force of 13N. It took him 3 s to
push the box, and he used a power of 13W. What distance did he push the box
back across the floor?
19. Tiffany pushes a box across the floor 19m with a force of 7N. She pushes the box for
7s. How much power did Tiffany use to push the box?
20. Johnathon des 35J of work when pushing a box across the classroom floor over a time
period of 7s. How much power did Johnathon use?