A stone is dropped from a height of 40 m. How much time will it take to reach the ground? With what velocity will it strike the ground?

Answer 1

You can find the velocity from the energy equation v =SQRT(2*g*h) where v = velocity, g = gravity acceleration (9.8 m/sec²), and h = height

Then

v = SQRT(2*9.8*40) = 28 m/sec

and

with no initial velocity Time = v/g = 28/9.8 = 2.86 seconds