Answer: Uh here
Explanation:
s=h=20
a=g=±10m/s=10m/s (since it is dropped)
v^2-u^2= 2as
v^2=2x10x20 (u=0; it is dropped not thrown)
v=20m/s
for calculating time
we know,
v=u+at
20= 0+ 10xt
t=2seconds
thus, it will attain a speed of 20m/s before touching the ground, but the time taken to reach the ground is 2seconds. Because the velocity is not uniform but acceleration/gravity is. If still there is any confusion. Try the same problem with 80 of height.
