“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.
NCERT Solutions for Class 9 Science Chapter 8 Force and laws of Motion
Page No. 91 Question 2.
9th Science Chapter 9 Force and Laws of Motion
NCERT Academic Session 2023-2024
CBSE Board and Others state Board
Description:
Force is a push or pull affecting an object’s motion or rest. Newton’s Laws of Motion state: 1. Objects stay at rest or in motion unless acted upon, 2. Force equals mass times acceleration, 3. Every action has an equal and opposite reaction, defining how forces influence motion.
n the series of events involving the football being kicked and passed among players, let’s pinpoint the moments where the velocity of the ball changes and the corresponding force agents:
1. First Kick by the Football Player:
– Velocity Change: The initial kick by the football player alters the ball’s velocity from rest to a specific speed and direction, initiating its movement.
– Force Agent: The football player provides the force by kicking the ball, initiating its motion.
2. Kick Towards the Goal by Another Player:
– Velocity Change: The second player’s kick redirects the ball’s velocity, changing both its speed and trajectory as it moves towards the goal.
– Force Agent: The second player applies force to redirect the ball’s path towards the goal.
3. Collection by the Goalkeeper:
– Velocity Change: When the goalkeeper collects the football, the ball’s velocity changes from its previous trajectory to zero, effectively halting its motion.
– Force Agent: The force exerted in stopping the ball’s movement primarily comes from the goalkeeper’s hands or body.
4. Kick by the Goalkeeper Towards Own Teammate:
– Velocity Change: As the goalkeeper kicks the ball towards a player of their team, the ball’s velocity shifts from rest to a certain speed and direction, setting it in motion again.
– Force Agent: Similar to the initial kick, the force is applied by the goalkeeper’s kick, propelling the ball towards their teammate.
In summary, these are the moments where the velocity of the ball changes:
1. Initial kick by the football player.
2. Kick towards the goal by another player.
3. Collection by the goalkeeper, halting the ball’s motion.
4. Kick by the goalkeeper towards their own teammate.
The individuals supplying the force in each instance are:
1. Football player for the initial kick.
2. Second player for kicking towards the goal.
3. Goalkeeper using their hands or body to stop the ball.
4. Goalkeeper for the kick towards their teammate.