An object of mass, m is moving with a constant velocity, v. How much work should be done on the object in order to bring the object to rest?

We know that, \( E_k \ = \ \frac{mv^2}{2} \)

The kinetic energy of an object at rest = 0

\(\therefore \) Work done = change in kinetic energy = \( \frac{mv^2}{2} - 0 \) = \( \frac{mv^2}{2} \)