A body is drop from rest at hight of 80m.how longs does it take to rich the ground?(g=10ms–², ignore air resistance

1 answer

a = -g = -10 m/s^2
v = Vinitial - 10 t but Vinitial is 0 so v = - 10 t
h = Hi + Vinitial t - (1/2)(10) t^2
0 = 80 - 5 t^2
t^2 = 16
t = 4 seconds