Question

The foot of an elephant has an area of 257 cm$^2$. If the mass of an elephant is 2200 kg. Find the pressure exerted by the elephant on the ground. (Take g=10 m/s$^2$ )

Answer 1

Hint:- In this question we are going to calculate the pressure exerted by the elephant on ground.
We know the pressure is the force per unit area can be written as mathematical expression.
$P = \dfrac{F}{A}$
We can use this formula to solve these types of questions.

Complete step-by-step solution :
Step 1
As we know from the definition of pressure.
Force per unit area is called pressure
$P = \dfrac{F}{A}$ ............. (1)
Here $F = mg$ gravitational force by earth on elephant or can say the weight of elephant
We found the force exerted by elephant on ground is given by
$F = mg \\\ \Rightarrow F = 2200 \times 10 \\\ \Rightarrow F = 22000 \\\$
$F = 22000$ N

Step 2
Second thing we need the area which is given in the question
$A = 275$ cm$^2$
Converting given area in m$^2$
We know 1 cm= 10$^{-2}$ m
So 1 cm$^2$ = 10$^{-4}$ m$^2$
$A = 275 \times {10^{ - 4}}$ m$^2$
Step 3
From the equation (1) we can find the pressure exerted by the elephant on the ground
$P = \dfrac{F}{A} \\\ \Rightarrow P = \dfrac{{22000}}{{275 \times {{10}^{ - 4}}}} \\\$
$P = 80 \times {10^4}$ Newton/m$^2$
So finally we get the answer the pressure exerted by the elephant on the ground is $80 \times {10^4}$ N/m$^2$

Note:- We can solve these types of questions very easily by this simple method.
One thing we should always remember is that the unit of all physical quantities should be in one system like the MKS system or SI system.
Some students got the wrong answer due to these types of silly mistakes.
So always make sure all units should be in the same system.