Question

a ball is thrown upwards 20m/s let g= 10m/s*s at what time it comes back

Answer 1

10m/s square is the correct answer

Answer 2

Hi!

u=20m/s
v=0 (at highest point velocity is 0)
g= 10m/s^2 , -10m/s^2, as work is done against the gravity.
t=?

v-u=at
0-20=-10×t
-20=-10t
20/10=t
t=2s

Hope it helps...!!!