Question

A hockey player receives a corner shot at a speed of 15 m/s at an angle of 30? with the y-axis and then shoots the ball of mass 100 g along the negative x-axis with a speed of 30 m/s. If it remains in contact with the hockey stick for 0.01 s, the force imparted to the ball in the x-direction is

• A. 281.25 N
• B. 187.5N
• C. 562.5 N
• D. 375 N

Answer 1

Answer: (D)

If a constant force $\overrightarrow{F}$ is applied on a body for short interval of time $\Delta t$ , then the impulse this force is $F\times \Delta t$ .
Since, impulse = change in momentum $(\Delta p)$
$\therefore$ $F\times \Delta t=\Delta p$
$\Rightarrow$ $F=\frac{\Delta p}{\Delta t}$ Change in $x-$ direction $F=\frac{m[30-(-15\sin {30}^o)]}{0.01}$ $F=\frac{0.1\times 37.5}{0.01}=375N$ Note: Unit of impulse is same as that of momentum.