Question

.??????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 kicks 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.

Answer 1

☆$\red {HELLO\:DEAR}$☆

• The velocity of the ball changes four times.

• As a football player kicks the football, its speed changes from zero to a certain value.

• As a result, the velocity of the ball gets changed.

• In this case, the player applied a force to change the velocity of the ball.

• Another player kicks the ball towards the goal post.

• As a result, the direction of the ball gets changed.

• Therefore, its velocity also changes.

• In this case, the player applied a force to change the velocity of the ball.

• The goalkeeper collects the ball. In other words, the ball comes to rest.

• Thus, its speed reduces to zero from a certain value. The velocity of the ball has changed.

• In this case, the goalkeeper applied an opposite force to stop/change the velocity of the ball.

• The goalkeeper kicks the ball towards his team players.

• Hence, the speed of the ball increases from zero to a certain value.

• Hence, its velocity changes once again.

• In this case, the goalkeeper applied a force to change the velocity of the ball.

☆$\green {VISHU\:PANDAT}$☆

☆$\blue {FOLLOW\:ME}$☆

Answer 2

Explanation:

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