Question

Calculate the pressure on the ground from an 80 kg woman leaning on the back of one of her shoes with a 1cm diameter heel, and calculate the pressure of a 5500 kg elephant with 20 cm diameter feet balancing on one foot.

Answer 1

Answer:

Pressure of woman will be $99.87\times 10^5N/m^2$

Pressure of the elephant will be $1716560.50N/m^2$

Explanation:

We have given that mass of the woman m = 80 kg

Acceleration due to gravity $g=9.8m/sec^2$

Diameter of shoes = 1 cm =0.01 m

So radius $r=\frac{d}{2}=\frac{0.01}{2}=0.005m$

So area $A=\pi r^2=3.14\times 0.005^2=7.85\times 10^{-5}m^2$

We know that force is given  F = mg

So $F=80\times 9.8=784N$

Now we know that pressure is given by $P=\frac{F}{A}=\frac{784}{7.85\times 10^{-5}}=99.87\times 10^5N/m^2$

Now mass of elephant m = 5500 kg

So force of elephant = 5500×9.8 = 53900 N

Diameter = 20 cm

So radius r = 10 cm

So area will be $A=3.14\times 0.1^2=0.0314m^2$

So pressure will be $P=\frac{53900}{0.0314}=1716560.50N/m^2$