The momentum $p$ (in $kg \cdot m/s$) of a particle is varying with time $t$ (in $s$) as $p = 2 + 3t^2$. The force acting on the particle at $t = 3 \, s$ will be ......... $N$.

The time taken by a force of $2 \ N$ to produce a change of momentum of $0.4 \ kg \ m \ s^{-1}$ in a body is: (in $s$)

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

$A$ vehicle of $100\, kg$ is moving with a velocity of $5\, m/s$. To stop it in $\frac{1}{10}\, s$,the required force in the opposite direction is ........... $N$.

The velocity $(v)$ of a particle (under a force $F$) depends on its distance $(x)$ from the origin (with $x > 0$) as $v \propto \frac{1}{\sqrt{x}}$. Find how the magnitude of the force $(F)$ on the particle depends on $x$.

When a body is acted upon by a constant force,then which of the following quantities remains constant?