Name the unbalanced force which slows down a moving bicycle when we stop pedalling it.

Show that the rate of change of momentum $=$ mass $\times$ acceleration.

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.

$A$ man pushes a box of mass $50\, kg$ with a force of $80\, N$. What will be the acceleration of the box due to this force? What would be the acceleration if the mass were doubled?

While dusting a carpet,we suddenly jerk or beat it with a stick because:

$(a)$ Define inertia. There are three solid balls, made of aluminium, steel, and wood, of the same shape and volume. Which of them would have the highest inertia? Why?
$(b)$ Describe in brief an activity to illustrate the property of inertia of rest.