$A$ machine gun can fire $50 \, g$ bullets with a velocity of $150 \, m s^{-1}$. $A$ $60 \, kg$ stone is moving towards the machine gun with a velocity of $10 \, m s^{-1}$. How many bullets must be fired from the gun to just stop the stone in its tracks?

$A$ large truck and a car,both moving with speed $v$,have a head-on collision and both of them come to a halt after that. If the collision lasts for $10 \ s$:
$(i)$ Which vehicle experiences the greater force of impact?
$(ii)$ Which vehicle experiences the greater momentum change?
$(iii)$ Which vehicle experiences the greater acceleration?
$(iv)$ Why is the car likely to suffer more damage than the truck?

$(a)$ How much momentum will an object of mass $10 \ kg$ transfer to the floor if it falls from a height of $0.8 \ m$? $(g = 10 \ m s^{-2})$
$(b)$ Explain why it is difficult for a fireman to hold a hose,which ejects a large amount of water at a high velocity.

$(a)$ Two objects of masses $100\, g$ and $200\, g$ are moving along the same line and direction with velocities $2\, m s^{-1}$ 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 of the second object.
$(b)$ If a man jumps out from a boat,the boat moves backwards. Why?

$A$ player catching a moving ball moves his hand backwards. Why?

$(a)$ State Newton's first and third laws of motion.
$(b)$ $A$ car of mass $1800 \, kg$ moving with a speed of $10 \, m s^{-1}$ is brought to rest after covering a distance of $50 \, m$. Calculate the force acting on the car.