$A$ person holds a ball of mass $0.25 \ kg$ in his hand and throws it,so that it leaves his hand with a speed of $12 \ m \ s^{-1}$. In this process,if his hand moved through a distance of $0.9 \ m$,then the net force acted on the ball is (in $N$)

$A$ bullet of mass $20 \,g$ moving with $500 \,ms^{-1}$ is pierced $1 \,cm$ into a wooden block. The retarding force experienced by the bullet is:

When a force $F$ given by $F=(6 \hat{i}-18 \hat{j}+10 \hat{k}) \text{ N}$ acts on a body,it imparts an acceleration of $8 \text{ m/s}^2$. Find the mass of the body.

$A$ particle of mass $2/3 \, kg$ with velocity $v = -15 \, m/s$ at $t = -2 \, s$ is acted upon by a force $F = k - \beta t^2$. Here,$k = 8 \, N$ and $\beta = 2 \, N/s^2$. The motion is one-dimensional. Then,the speed at which the particle acceleration is zero again,is ........... $m/s$.

$A$ force of $100 \, dynes$ acts on a mass of $5 \, g$ for $10 \, s$. The velocity produced is ......... $cm/s$.

$A$ cricket ball of mass $50 \ g$ having velocity $50 \ cm \ s^{-1}$ is stopped in $0.5 \ s$. The force applied to stop the ball is (in $N$)