Fundamentals

During a collision, an object experiences an impulse that causes and is equal to the momentum change. That is, Impulse = ∆momentum. The impulse is equal to F•∆t and the momentum change is equal to ∆p. And so one can say that ...
 

F • ∆t = ∆p


where the ∆p is equal to the final momentum minus the initial momentum (pfinal - pinitial). And finally, since momentum is the product of mass times velocity, these initial and final values of momentum can be related to the initial and final values of velocity by the equaion ...
 

p = m • v
 

There are four tables for this difficulty level. Each table has the same basic structure with simply different numerical values. Here is one of the versions:
 

Version 1:

An object with mass (m) is in motion with an initial velocity (vinitial). It then experiences an impulse resulting in a final velocity (vfinal) and a final momentum (pfinal) that are different than the initial values.
 
Complete the following table. Tap on a table cell to enter or edit an answer.

 

 

How to Think About This Situation

Help for Wizard Difficulty Level

You can think of this difficulty level as involving five problems. Each row is a problem. And each row is independent of any other row. That is, for Row B, all you need to know is Row B information in order to determine the blanks in Row B. There are three ideas that you will use in determining the three blanks in each row. Here they are:


Mass-Velocity-Momentu
The momentum of a object can be mathematically related to the mass and velocity by the equation ...

p = m•v

This relationship allows you to relate columns 1, 2, and 3 to one another. It also allows you to relate columns 1, 5, and 6 to one another. Knowing any two values in these columns allows you to calculate the value of a third column.



Impulse and Momentum Change
As mentioned in the Fundamentals section above, the impulse an object experiences is equal to the momentum change. There is an impulse column (fourth column) but there is no explicit momentum change column. But if you can determine the momentum change from the impulse, then you can relate columns 3 and 5 to one another. See the next section below.



Momentum Change and the Initial and Final Momentum
A change in any quantity can be perceived as the initial value of that quantity subtracted from the final value of that quantity. Applied to momentum, we can say that ...

∆p = pfinal - pinitial

Understanding this equation and the previous section (immediately above) allows you to relate values in columns 3, 4, and 5 to each other.


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Try these links to The Physics Classroom Tutorial for more help with using the F•∆t = ∆p equation to analyze a collision:

Impulse and Momentum Change

or view the corresponding Video on the topic.
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