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

Name the physical quantity whose $SI$ unit is "newton".

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 velocity. If no, provide a reason.

Two identical bullets are fired,one by a light rifle and another by a heavy rifle with the same force. Which rifle will hurt the shoulder more and why?

$(a)$ Why do we jerk wet clothes before spreading them on a clothesline?
$(b)$ Fruits fall off the branches when a strong wind blows. Give a reason.

Two cars each of mass $1000 \ kg$ are moving in a straight line but in opposite directions. The velocity of each car is $5 \ m s^{-1}$ before the collision during which they stick together. What will be the velocity of the combined cars after collision (in $m s^{-1}$)?