Question

A bus can be stopped by applying a retarding force F when it is moving with a speed v on a level road. The distance covered by it before coming to rest is s. If the load of the bus increases by 50 % because of passengers, for the same speed and same retarding force, the distance covered by the bus to come to rest shall be

• A. 1.5 s
• B. 2 s
• C. 1 s
• D. 2.5 s

Answer 1

The correct option is A

1.5 s

Work done by Retarding force = Loss in Kinetic Energy,
Retarding force (F) $\times$ distance covered (x) = Kinetic energy $\left(\frac{1}{2}m{v}^2\right)$

If v and F are constants then $x\propto m\therefore \frac{x_2}{x_1}=\frac{m_2}{m_1}=\frac{1.5m}{m}=1.5\Rightarrow x_2=1.5s.$