A golf ball G G\,G is projected from a point on level ground with velocity k(4i+3j)ms−1k(4\mathbf{i} + 3\mathbf{j})\text{ms}^{-1}k(4i+3j)ms−1, where k k\,k is a positive constant. The greatest height reached by G G\,G is 15 m above the ground.
Find the exact value of kkk.
Find the horizontal distance travelled by the ball before it hits the ground.