Question

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?

Answer 1

Answer:

64 kPa

Explanation:

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

$p=\frac{F}{A}$

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

$p=\frac{F}{2A}=32 kPa$ (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

$p'=\frac{F}{A} = 2(\frac{F}{2A})=2p$

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

$p'=2(32)=64 kPa$