Physics Help

Question

An 800 N board is moved a distance of 0.06 m by a screw. If the efficiency of the screw is 18%, what was the input work on the screw?
A. 48 J
B. 144 J
C. 267 J
D. 480 J

Answer 1

Assuming that the weight was done against gravity, the work done on the board is 800 N * 0.06 m = 48 J.

Since the screw is not 100% efficient, extra work must be done using the screw.   Wout/Win = 0.18

 

Win = Wout/0.18 

 

48J / 0.18 = 267 J.