$A$ $8000 \,kg$ 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 net accelerating force (in $N$).

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.

$A$ hammer of mass $500 \,g$,moving at $50 \,m/s$,strikes a nail. The nail stops the hammer in a very short time of $0.01 \,s$. What is the force (in $N$) of the nail on the hammer?

$A$ $8000 \,kg$ 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.

$A$ stone of $1\, kg$ is thrown with a velocity of $20\, m\ s^{-1}$ across the frozen surface of a lake and comes to rest after travelling a distance of $50\, m$. What is the force of friction (in $N$) between the stone and the ice?

$A$ truck starts from rest and rolls down a hill with a constant acceleration. It travels a distance of $400 \, m$ in $20 \, s$. Find the force (in $N$) acting on it if its mass is $7 \, \text{tonnes}$ $(1 \, \text{tonne} = 1000 \, kg)$.