Question

A truck and a car are moving on a smooth level road such that the K.E. associated with them is the same. Which one will cover a greater distance when brakes are applied to them simultaneously?

• A. Car
• B. Truck
• C. Both will cover the same distance
• D. None of these

Answer 1

The correct option is C

Both will cover the same distance

1. According to the work-energy theorem, the work done by a force on a body is equal to a change in its kinetic energy.
2. The car and truck have the same kinetic energy. When the brakes of both car and truck are applied, retardation forces will act on both.
3. Their kinetic energy will be used to do work against the force which is equal to the product of retardation force and the displacement.
4. As kinetic energy is the same, the work done will be the same.

Thus, both the car and the truck will cover the same distance before stopping.

Hence, option (c) is correct.