Question

A Shaolin monk of mass 60 kg is able to do a ‘finger stand’: he supports his whole weight on his two index fingers, giving him a total contact area of 4 cm 2 with the ground. Calculate the pressure he exerts on the ground (include units), and write your answer to two significant figures.

Answer 1

Answer:

P = 1471500 [Pa]

Explanation:

We must remember that pressure is defined as the relationship between Force over the area.

$P=F/A$

where:

P = pressure [Pa] (units of pascals)

F = force [N] (units of Newtons)

A = area of contact = 4 [cm²]

But first we must convert from cm² to m²

$A = 4[cm^{2}]*\frac{1^{2} m^{2} }{100^{2} cm^{2} }$

A = 0.0004 [m²]

Also, the weight should be calculated as follows:

$w = m*g$

where:

m = mass = 60 [kg]

g = gravity acceleration = 9.81 [m/s²]

Now replacing:

$w = 60*9.81\\w = 588.6[N]$

And the pressure:

$P=588.6/0.0004\\P=1471500 [Pa]$

Because 1 [Pa] = 1 [N/m²]