A circus performer on a pair of stilts exerts a pressure of 32 kPa on the ground. If the performer stands on one stilt, what pressure does the stilt exert on the ground?

64 kPa

Explanation:

The pressure exerted by a force on a surface is given by

where

p is the pressure

F is the force

A is the area on which the force is exerted

In this problem, let's call:

F = the weight of the performer, which is the force

A = the area of 1 stilt

At the beginning, the performer is standing on both stilts, so the area on which he exerts pressure is 2A. So the pressure is

(1)

Later, he stands on one stilt only. The force exerted is still the same (his weight), however, the area is now reduced to A; therefore, the new pressure is

which is twice the value calculated in (1); so, the new pressure is