Question

Consider a ball falling toward earth. why is the momentum of the ball not conserved? in what system that includes the falling ball is the momentum conserved? "

Answer 1

The momentum of a falling ball towards the Earth is not conserved due to external forces acting on it, such as gravity. However, if we expand the system to include the Earth, momentum is conserved as a whole system.

Step-by-step explanation:

In the case of a ball falling towards the Earth, the momentum of the ball is not conserved. This is because external forces act on the ball during its fall, such as gravity pulling it downward. To consider a system where momentum is conserved, we can expand the system to include the Earth. While the ball's momentum changes, the Earth also recoils, conserving momentum as a whole. However, the effect on the Earth is negligible due to its much greater mass compared to the ball.

Answer 2

First, lets correct your concept. Momentum is still conserved in the system. the ball is falling towards th earth and the earth is also accelerating towards the ball. the forces betwwen the earth and the ball are the same by Newton's third law. but the rate of acceleration of the earth is neglectable seemingly to have no momentum, beacuse the earth has higher mass than the ball by F=ma. Therefore momentum is still conserved.