A girl of mass 50 kg is standing on her both feet, each of area 20 cm². Find out the pressure experienced by the girl (g = 10 m/sec²).

Steps to Solve

1. Identify the given data

The mass of the girl is given as ( m = 50 , \text{kg} ) and the area of each foot is ( A = 20 , \text{cm}^2 ).

2. Convert area to appropriate units

Since pressure is typically expressed in ( \text{N/m}^2 ) (Pascals), convert ( 20 , \text{cm}^2 ) to ( \text{m}^2 ): $$ 20 , \text{cm}^2 = 20 \times 10^{-4} , \text{m}^2 = 0.002 , \text{m}^2 $$

3. Calculate the force

The force exerted by the girl due to gravity can be calculated using: $$ F = m \cdot g $$ where ( g ) (acceleration due to gravity) is ( 10 , \text{m/s}^2 ). Thus: $$ F = 50 , \text{kg} \cdot 10 , \text{m/s}^2 = 500 , \text{N} $$

4. Calculate total area

The girl is standing on both feet, so the total area ( A_{total} ) is: $$ A_{total} = 2 \times A = 2 \times 0.002 , \text{m}^2 = 0.004 , \text{m}^2 $$

5. Calculate pressure

Pressure is defined as force divided by area: $$ P = \frac{F}{A_{total}} = \frac{500 , \text{N}}{0.004 , \text{m}^2} = 125000 , \text{N/m}^2 $$