Question

The weight of a rider, driving scooter is assumed to be evenly distributed on both the tyres. The area of contact of each tyre with the ground is $10c{m}^2$. If the pressure inside the tyres is 2 bar, find the mass of the rider. $(g=10m{s}^{-2})$

• A. 40 kg
• B. 50 kg
• C. 60 kg
• D. 70 kg

Answer 1

The correct option is A 40 kg

Area of contact of each tyre $=10c{m}^2$
Area of contact of two tyres (A)
$=2\times 10c{m}^2=20c{m}^2$
$=20\times {10}^{-4}{m}^2(\therefore 1c{m}^2={10}^{-4}{m}^2)$
$Pressure\left(P\right)=2bar=2\times {10}^{5}Pa(\therefore 1bar={10}^{5}Pa)$

Weight of the person$=pressure\times area$

$W=P\times A=2\times {10}^5\times 20\times {10}^{-4}=400N$

Weight of the person is 400 N.
Mass of the person (m)
$=\frac{W}{g}=\frac{400}{10}=40kg$

Therefore, the mass of the person is 40 kg.