A ball is thrown straight up that it reaches a max height of 30 meter. How long did it take the ball to go up? How fast was it going when it was 10 meter high from the ground?

Answer 1

(1/2) m Vi^2 at bottom = m g h at top
Vi^2 = 2 g h = 2 * 9.8 * 30
Vi = 24.2 m/s

v = Vi - g t
0 = 24.2 - 9.8 t
t = 2.47 s

(1/2) m Vi^2 = (1/2) m v^2 + m g (10)
24.2^2 = v^2 + 98*2
v = 19.7 m/s