(a) A man weighing 704 N lies on a bed of nails. Find the average pressure exerted by a nail on his skin if there are 1010 nails and the flattened point on each nail has a radius of 0.500 mm.
(b) Calculate the pressure exerted on the skin by an acupuncture needle of radius 0.100 mm applied with a force of 4.40 N.