Question

The force, F, needed to break a board in a martial arts class varies inversely with the length, L, of the board. If it takes 24 pounds of pressure to break a board 2.5 feet long, how many pounds of pressure would it take to break a board that is 18 inches long?
Steve
LF=k, so you want F such that

18F = (2.5*12)*24

watch the units -- you cannot just plug in inches and feet without making adjustments