7 Questions
| Total Attempts: 171

Questions and Answers

- 1.How much power is needed to cut a lawn in 50 minutes if the work involved is 100,000J? Hint: you must convert minutes to seconds. 50 minutes times 60 seconds ? ___Watts (put only the numeric value to the nearest WHOLE number).
- 2.As you push a lawn mover, the horizontal force is 300 N. If you push the mower a distance of 500 M, how much work do you do? _____ J
- 3.A librarian lifts a box of books that weighs 93 N a distance of 1.5 m. How much work does she do? ____J
- 4.A teacher does 140 J of work in 20 s. How much power did he use? ____W
- 5.You do 100 J of work in pulling out a nail with a claw hammer. If the hammer does 70 J of work, what is the hammer's efficiency? ______%
- 6.Find the efficiency of a machine if the input work is 150 J and the output work is 90 J. _____%
- 7.To lift a crate, a pulley system exerts a force of 2,750 N. Find the mechanical advantage of the pulley system if the input force is 250 N. ____