Which would require a greater force $-$ accelerating a $1\, kg$ mass at $10\, m s^{-2}$ or a $2\, kg$ mass at $4\, m s^{-2}$?

Air is blown onto a sail attached to a boat from an electric fan placed on the boat. Will the boat start moving?

If someone jumps to the shore from a boat,the boat moves in the opposite direction. Explain.

$A$ cricket ball of mass $70 \, g$,moving with a velocity of $0.5 \, m s^{-1}$ is stopped by a player in $0.5 \, s$. What is the force applied by the player to stop the ball (in $, N$)?

$A$ car of mass $1000 \, kg$ moving with a velocity of $15 \, m/s$ collides with a tree and comes to rest in $5 \, s$. What will be the force exerted by the car on the tree?

Explain the following:
$(i)$ Why do we jerk wet clothes before spreading them on a line?
$(ii)$ Why does dust fly off when a carpet is hit with a stick?
$(iii)$ Why do fruits fall off the branches in a strong wind?
$(iv)$ Why does a pillion rider fall forward when the driver of a two-wheeler suddenly applies brakes?