[cc100]

here we go:

a man lies on a bed of nails, so that his whole weight is supported on their tips. his weight is 650N and the area of each nail tip is is 1 mm2(squared). the pressure on his skin from each nail can be calculated in the samne way as the stress. if a pressure of 4 N mm-2 is the maximum he can withstand without pain, calculate the smallest number of nails he must lie on in order not to be hurt.

(this may help: pressure= force divided by area, where pressure is in N mm-2, force is in N, area is in mm2(squared)


i know its a toughie but , can you help??