A ball is projected from a point O on the edge of a vertical cliff. The horizontal and vertically upward components of the initial velocity are 7ms-1 and 21ms-1 respectively. At the time t seconds after the projection the ball is at the point (x,y) referred to horizontal and vertically upward axes through O. Air resistance may be neglected.
(i) Express x and y in terms of t, and hence show that y= 3x- 0.1x2
The ball hits the sea at a point which is 25m below the level of O.
(ii) Find the horizontal distance between the cliff and the point where the ball hits the sea.