Question

Answer the following questions:

1) In the following example, try to identify the number of times the velocity of the ball changes :
" A football player kicks a football to another player of his team who kicked the football towards the goal. The goalkeeper of the opposite team collects the football and kicks it towards a player of his own team."
Also identify the agent supplying the force in each case.

2) Explain why some of the leaves may get detached from a tree if we vigorously shake its branch.

3) Why do you fall in the forward direction when a moving bus brakes to a stop and fall backwards when it accelerates from rest?

Answer 1

Dear student,

1) The velocity of football changes four times.

First, when a football player kicks to another player, second when that player kicks the football to the goalkeeper. Third when the goalkeeper stops the football. Fourth when the goalkeeper kicks the football towards a player of his own team.

Agent supplying the force:

→ First case – First player

→ Second case – Second player

→ Third case – Goalkeeper

→ Fourth case – Goalkeeper

2) The answer of this cause lies behind the Newton’s First Law of Motion. Initially, leaves and tree both are in rest. But when the tree is shaken vigorously, tree comes in motion while leaves have tendency to be in rest. (Some leaves of a tree get detached when we shake its branches vigorously because branches comes in motion while the leaves tend to remain at rest due to inertia of rest.)Thus, because of remaining in the position of rest some of the leaves may get detached from a tree if we vigorously shake its branch.

3) In a moving bus, a passenger moves with the bus due to inertia of motion. As the driver applies brakes, the bus comes to rest. But, the passenger tries to maintain to inertia of motion. As a result, a forward force is exerted on him.

Similarly, the passenger tends to fall backwards when the bus accelerates from rest because when the bus accelerates, the inertia of rest of the passenger tends to oppose the forward motion of the bus. Hence, the passenger tends to fall backwards when the bus accelerates forward from rest.

Hope you understood
Regards