A ball is thrown vertically upward with an initial velocity of 20m/s. Take the acceleration due to gravity g=10m/s2 acting downward.
(i) Write the two equations of motion that are applicable to the upward journey of the ball, clearly identifying each physical quantity involved.
(ii) Determine the time taken by the ball to reach its highest point.
(iii) Calculate the maximum height reached by the ball.
(iv) Show, by an appropriate substitution in an equation of motion, that the magnitude of the velocity with which the ball returns to the point of projection is the same as its initial velocity. Compute this velocity just before it strikes the ground.