Question

A player caught a cricket ball of mass $150g$moving at the rate of $20m/s$. If the catching process be completed in $0.1s$ the force of the blow exerted by the ball on the hands of the player is

• A. $0.3N$
• B. $30N$
• C. $300N$
• D. $3000N$

Answer 1

The correct option is B

$30N$

Step 1: Given data

mass of cricket ball, $m=150g$

$=0.150Kg[As,1Kg=1000g]$

Initial velocity of cricket ball, $u=20m/s$

Final velocity of cricket ball, $v=0m/s$ [As, after catching ball will stop]

Time taken for the catch process, $t=0.1s$

Step 2: Find the force, $\mathit{F}$

The magnitude of change in momentum, $\left|∆P\right|=\left|mv-mu\right|$

$$\begin{gathered} =\left|0.150\times 0-0.150\times 20\right| \\ =3Kg.m/s \end{gathered}$$

Average force exerted by the ball, $F_{av}=\Delta P/\Delta t$ [From Newton's second law of motion]

$$\begin{gathered} =[3kg.m/s]/[0.1sec] \\ =30N \end{gathered}$$

Hence, option (B) is correct.