Question

A ball is thrown vertically upward attains a maximum height of 45 m. The time after which velocity of the ball become equal to.half the velocity of projection? (use g=10m/s2)

Answer 1

v^2 = u^2 + 2as
0 = u^2 + 2(-10)45
u^2 = 900
u = 30 m/s
v = u + at
15 = 30 + (-10)t
10t = 15
t = 1.5 s