Question

when a cricket ball is thrown vertically upwards ,it reaches a maximum height of 5m.a)what was the initial speed of the ball.b)how much time is taken by the ball to reach the highest point.

Answer 1

Initial velocity, u=?

Final velocity, v=0

Acceleration due to gravity, g=-10m/s2

Height, h=5 m

(a) For a freely falling body:

v2 = u2 + 2gh

(0)2 = u2 + 2 x(-10)x 5

0= u2 -100

u2 = 100

So, u=10m/s

(b) Using relation, v=u + gt

0 = 10 + (-10) t

-10= -10 t

t=1sec

Answer 2

a)10 m/s (taking g=10m/s2)
b)1s