Question

A man pulled a nail our of a board with a crowbar. The nail was 2 in. from the fulcrum of the crowbar, and the effort applied was 36 in. from the fulcrum. If the theoretical effort applied was 10 lb., what was the force of friction between the board and the nail? How far did the hand have to move in order to move the nail one inch?

I do not know where to start.

17 years ago