10 - dp is related to the collision force F as The total...

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10.1. Introduction In a collision, strong mutual forces act between a few particles for a short time. These internal forces are significantly larger than any external forces during the time of the collision. The laws of conservation of linear momentum and energy, applied to the "before" and "after" situations, often allows us to predict the outcome of a collision. A great deal can be learned about the interactions between the colliding particles from the observed collision products. Note : external forces are small (and are ignored) during the collision particles before and after the collision can be different (for example: nuclear reactions) the collision force does not need to be a contact force 10.2. Impulse Suppose a force F acts during a collision. The result of the collision force will be a change in the momentum of the particles involved. The amount of change depends not only on the average value of the force, but also on the time period during which it acts. The change in momentum
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Unformatted text preview: dp is related to the collision force F as The total change in the of momentum during the collision is given by The right hand side of this equation is a measure of both the strength and the duration of the collision force. It is called the collision impulse J : The unit of the impulse is N . s. From the definition of the impulse J we see that the relation between the impulse and the change of momentum is given by If the average collision force F av acts during a time period equal to [Delta]t, the impulse J is equal to F av [Delta]t = J Sample Problem 10-1 A baseball of mass m in horizontal flight with speed v i is struck by a batter. After leaving the bat, the ball travels in the opposite direction with a speed v f . What impulse J acts on the ball while it was in contact with the bat ? If the impact time is [Delta]t, what is the average force that acts on the baseball ? What is the average acceleration of the baseball during this period ?...
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This document was uploaded on 11/25/2011.

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