- #1
hideelo
- 91
- 15
Lately I have been thinking about the conservation of linear momentum, and there are two cases that I can think of that seem to violate the conservation principle.
1. Throwing a rubber ball against a wall. Imagine you threw a rubber ball in what we will call the positive x direction, if the ball were to hit a wall we all know from experience what will happen next, the ball will bounce off the wall. However, the ball started off with linear momentum in the plus x direction and now it has its momentum in the negative x direction. How in this case is momentum conserved?
2. Imagine you had a spinnng wheel which you gently lower down onto the ground, as soon as it touches the ground it will start moving away from you. Once again, before it touches the ground it has only angular momentum and no linear momentum, yet as soon as it touches the ground it will move away from you and therefore must have linear momentum. Where is the momentum coming from?Thank you
1. Throwing a rubber ball against a wall. Imagine you threw a rubber ball in what we will call the positive x direction, if the ball were to hit a wall we all know from experience what will happen next, the ball will bounce off the wall. However, the ball started off with linear momentum in the plus x direction and now it has its momentum in the negative x direction. How in this case is momentum conserved?
2. Imagine you had a spinnng wheel which you gently lower down onto the ground, as soon as it touches the ground it will start moving away from you. Once again, before it touches the ground it has only angular momentum and no linear momentum, yet as soon as it touches the ground it will move away from you and therefore must have linear momentum. Where is the momentum coming from?Thank you