A brick of mass 0,5 kg possesses 100J of gravitational potential energy when held at a certain height above the ground.How long will it take to reach the ground when it is released?

Answer 1

mgh = 100
.5*9.8*h = 100
h=20.4m

now, knowing that h = 1/2 at^2 it should not be hard to come up with t = 2.04s

same answer if you combine the formulas to get

t^2 = 2E / mg^2