A stone is projected vertically upwards with velocity 40 m/s. Show that the stone will reach the point of projection with the same velocity.

Answer 1

hmax = (V^2-Vo^2)/2g.
hmax = (0-1600)/-19.6 = 81.6 m.

V^2 = Vo^2 + 2g*hmax.
V^2 = 0 + 19.6*81.6 = 1600
V = 40 m/s.