A tower is 24 m high. A stone is projected upwards from the tower, at a velocitry of 24,5 m/s. Calculate how long it would take the stone to reach the ground at the roof of the tower.

Answer 1

Vf = Vo + g*Tr = 0.
24.5 + (-9.8)Tr = 0.
-9.8Tr = 24.5
Tr = 2.5 s. = Rise time.

Tf1 = Tr = 2.5 s = Time to fall back to roof.

h = Vo*t + 4.9*t^2 = 24 m.
24.5*t + 4.9t*2 = 24.
4.9t^2 + 24.5t -24 = 0.
Use Quad. Formula.
t = 0.839 s. = Time to fall from top of roof to gnd.

T = Tr + Tf1 + t = Tme to reach gnd.

Answer 2

5.839 s