Problem

A ball is projected with a velocity

20 \text{ ms}^{-1}

at an angle to the horizontal. In order to have the maximum range. Its velocity at the highest position must be a.

10 \text{ ms}^{-1}

14 \text{ ms}^{-1}

18 \text{ ms}^{-1}

16 \text{ ms}^{-1}