The momentum of a body of given mass is proportional to its

Two friends on roller-skates are standing $5\, m$ apart facing each other. One of them throws a ball of $2\, kg$ towards the other,who catches it. How will this activity affect the position of the two? Explain your answer.

If the time taken to bring a ball to rest from a certain velocity $v$ is reduced to half,what will be the changes in values of
$(a)$ Initial and final momentum.
$(b)$ Change of momentum.
$(c)$ Rate of change of momentum.

$A$ goalkeeper in a game of football pulls his hands backwards after holding the ball shot at the goal. This enables the goalkeeper to

An object experiences a net zero external unbalanced force. Is it possible for the object to be moving with a non-zero velocity? If yes,state the conditions that must be placed on the magnitude and direction of the velocity. If no,provide a reason.

The rate of change of momentum is