A circus performer is putting together an act that involves lying on a bed of nails without getting hurt. The tip of each nail h
as a radius of 1 mm and the performer has a mass of 65 kg. A typical human pain threshold for pressure on the skin is about 0.40.4MPa (1\text{MPa} = 10^61MPa=10 6 Pa). This is the minimum pressure that causes a sensation of pain. If the performer stepped on a single nail, what pressure would the nail exert on his foot?
