The ratio of the change in linear momentum to the time taken for this change represents which physical quantity?

$A$ constant force acting on a body of mass $5\,kg$ changes its speed from $5\,ms^{-1}$ to $10\,ms^{-1}$ in $10\,s$ without changing the direction of motion. The force acting on the body is ......... $N$.

At a place where the acceleration due to gravity is $10\,m/s^2$,a force of $5\,kg-wt$ acts on a body of mass $10\,kg$ initially at rest. The velocity of the body after $4\,s$ is .......... $m/s$.

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.

$A$ force acting on a body of mass $5 \ kg$ is $(4 \hat{i} - 2 \hat{j} + 3 \hat{k}) \ N$. If the body is initially at rest,then the magnitude of its velocity at the end of $10 \ s$ in $m/s$ will be:

The driver of a three-wheeler moving with a speed of $36\; km/h$ sees a child standing in the middle of the road and brings his vehicle to rest in $4.0\; s$ just in time to save the child. What is the average retarding force (in $N$) on the vehicle? The mass of the three-wheeler is $400\; kg$ and the mass of the driver is $65\; kg$.