The Basic Idea

During a collision, an object experiences an impulse that changes its momentum. The impulse is equal to the momentum change. The impulse is the product of Force•∆Time. The momentum change is the product of Mass•∆Velocity. One can use the Force•∆Time = Mass•∆Velocity relationship to determine the set of collision parameters required to change the object's momentum from the initial state value to the final state value.
 

There are three very similar versions of this question. Each version provides a before-after diagram showing the initial and final momentum of an object. Five impulse values are presented. One of them would cause the specified momentum change. This is one of the three versions:

Version 1
Pre- and post-collision information is shown. Identify the collision parameters that are consistent with the indicated change in momentum. (A + sign indicates a rightward direction; a - sign indicates a leftward direction.)
 



a.  Impulse =  +15 N•s
b.  Impulse =  +4 N•s
c.  Impulse =  +7.5 N•s
d.  Impulse =  +8 N•s
e.  Impulse =  +30 N•s
 

How to Think About This Situation

The diagram in this question shows a pre-collision and a post-collision momentum value. The values indicate that the momentum has changed by a certain amount. The amount of momentum change can be calculated by subtracting the initial value from the final value. You will need to calculate this momentum change (∆p) before you can answer the question.
 
The momentum change is equal to the impulse. There are five impulse values provided. One of these impulse values is equal to the momentum change.
 

Try the links below to our Tutorial for more information:

Momentum

Impulse-Momentum Change Theorem

 


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