Two objects of masses $100\, g$ and $200\, g$ are moving along the same line and direction with velocities of $2\, m\, s^{-1}$ and $1\, m\, s^{-1}$, respectively. They collide and after the collision, the first object moves at a velocity of $1.67\, m\, s^{-1}$. Determine the velocity(in $m/s$) of the second object.

A motorcar of mass $1200\, kg$ is moving along a straight line with a uniform velocity of $90\, km/h$. Its velocity is slowed down to $18 \,km/h$ in $4\, s$ by an unbalanced external force. Calculate the acceleration and change in momentum. Also calculate the magnitude of the force required.

Two persons manage to push a motorcar of mass $1200\, kg$ at a uniform velocity along a level road. The same motorcar can be pushed by three persons to produce an acceleration of $ 0.2\, m \,s^{-2}$ . With what force(in $N$) does each person push the motorcar? (Assume that all persons push the motorcar with the same muscular effort.)

An automobile vehicle has a mass of $1500\, kg$. What must be the force(in $N$) between the vehicle and road if the vehicle is to be stopped with a negative acceleration of $1.7\, m \,s^{-2}$ ?

A $8000 \,kg$ engine pulls a train of $5 $ wagons, each of $2000\, kg$, along a horizontal track. If the engine exerts a force of $40000 \,N $ and the track offers a friction force of $5000\, N$, then calculate:  the acceleration(in $m/s^2$) of the train