Question

A cricketer stops a ball travelling at the speed of $10\text{m/s}$ in $0.5\text{s}$. If the mass of the ball is $0.1\text{kg}$ then the average force applied by the player is

• A. $-1\text{N}$
• B. $-2\text{N}$
• C. $-3\text{N}$
• D. $-4\text{N}$

Answer 1

The correct option is B $-2\text{N}$

Given that,
Initial speed of the ball, $u=10\text{m/s}$
Time taken to stop the ball, $t=0.5\text{s}$
Final speed of the ball, $v=0\text{m/s}$
Mass of the ball, $m=0.1\text{kg}$

According to newton's second law
Force, $F$ = Rate of change of momentum.
$F=\frac{\text{Final momentum -Initial momentum}}{\text{Time interval}}$
$\Rightarrow F=\frac{mv-mu}{t}$
$\Rightarrow F=\frac{(0.1\text{kg}\times 0\text{m/s})-(0.1\text{kg}\times 10\text{m/ s})}{0.5\text{s}}$
$F=-2\text{N}$