Question

When a cricket ball is thrown vertically upwards it reaches a maximum height of 5 metres ?what was the initial speed of the ball ? How much time is taken by the ball to reach the highest point ?

Answer 1

Answer:

10 m/ s and time=1second

Answer 2

Given:

• Max height reached by ball = 5 metres.

To find:

• Initial velocity ?
• Time taken to reach max height ?

Calculation:

First of all, let's assume that acceleration is constant and equal to g = 9.8 m/s².

Applying EQUATIONS OF KINEMATICS:

${v}^{2} = {u}^{2} + 2ah$

$\implies \: {0}^{2} = {u}^{2} + 2( -10)(5)$

$\implies \: {u}^{2} = 100$

$\implies \: u = 10 \: m {s}^{ - 1}$

So, initial velocity is 10 m/s.

Again, we say :

$v = u + at$

$\implies \: 0 = 10 + ( - 10)t$

$\implies \: 10t = 10$

$\implies \: t = 1 \: sec$

So, time needed to reach max height is 1 second.