Question

When a cricket ball is thrown vertically upwards, it reaches a maximum height of 5 metres.
(a) What was the initial speed of the ball ?
(b)) How much time is taken by the ball to reach the highest point ? $(g=10m{s}^{-2})$

Answer 1

(a) $v^2-u^2$=2 g h
and v = 0 (because velocity is 0 at the highest point)
$(g=10m{s}^{-2})$

$0^2-u^2=2-10\times 5$
u=√100=10
hence after solving it will come out to be initial velocity will be 10m/s

2) as v = u + gt
and v = 0
u = 10 m/s (as proved above)
$(g=10m{s}^{-2})$
hence,

$0=10+10t$ $\Rightarrow t=\frac{10}{10}=1s$