Question

an object is brought from a tower 180m high. how long does it take to reach the ground (take g=10m/s)

Answer 1

t={2h/g}^1/2
{2*180/10}^1/2
=6 sec.

Answer 2

u = 0

g = 10 m/s^2

S = 180m

t = ?

v =?

Using S = ut + 1/2at^2

180=1/2×10×t×t

360 = 10t^2

36 = t ^2

{t = 6sec}