# Energy conservation in Elastic collision

A question from my textbook is stated below

In an elastic collision

1. The initial kinetic energy is equal to the final kinetic energy
2. The final kinetic energy is less than the initial kinetic energy
3. The kinetic energy remains constant
4. The kinetic energy first increases then decreases

In the moment of collision the kinetic energy $$\left(\frac 12mv^2\right)$$ is $$0,$$ because $$v = 0$$, which means that the option $$3$$ is not correct.