(a) What is kinetic energy due to ? Derive an expression for it in case of a body of mass `m` moving with velocity `v`.
(b) If `W` is the work done to give a speed `v` to a car from rest, how much work is done to increase its speed to `2 v` ?

Explanation

### Step-by-Step Solution:

#### (a) What is kinetic energy? Derive an expression for it in case of a body of mass `m` moving with velocity `v`.

1. **Definition of Kinetic Energy**: Kinetic energy (KE) is the energy possessed by an object due to its motion. The faster an object moves, the more kinetic energy it has.

2. **Work-Energy Principle**: According to the work-energy principle, the work done on an object is equal to the change in its kinetic energy.

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