In case of an object vertically projected ,Show that the speed of the object upon reaching the point of projection is equal to the speed projection .

A stone projected vertically upward moves according to the law s=48t-16t^2 . The time taken by the stone to reach the point of projection is

(A): Two balls of different masses are thrown vertically upward with same speed, they will pass through their point of projection in the downward direction with the same speed. (neglect air resistance) (R): The maximum height and downward velocity attained at the point of projection are independent of the mass of the ball.

Show that time of ascent of a vertically projected body is equal to time of descent.