How would you include gravity in a momentum problem?

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The discussion revolves around incorporating gravity into momentum calculations involving two balls in an elastic collision. The scenario describes a large ball (mass m1) dropping and colliding with a smaller ball (mass m2) after falling from a height. The key challenge is understanding how gravity affects momentum and how to calculate the heights each ball will rise post-collision. The conversation highlights the importance of categorizing such problems as homework and suggests using a specific template for clarity. The thread concludes with a recommendation to post in the appropriate forum for further assistance.
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Say you have a big ball of mass m1 and a little ball on top of that of mass m2 (assume they are a small distance apart, like 1mm). Now let's drop these from a height of h so that the big ball will bounce off the ground and collide into the little ball in an elastic collision.

Now I know gravity would play a key role in this example but how would you perform calculations with it? I know F=p/t and momentum will not be conserved since there is an external force (gravity) so knowing this, how can you determine how high each ball will rise after the collision?
 
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How would you start on this problem? And by the way, in reality, "bouncing off the ground" is hardly an elastic collision.

Is this a homework problem? If so, you need to put it in the homework section and use the template.
 
This was just an example I thought of because all the problems I've done so far have pretty much been absent of external forces (such as a car collision).
 
Rnotaria said:
This was just an example I thought of because all the problems I've done so far have pretty much been absent of external forces (such as a car collision).
OK, then I ask again. How would you start on this problem?
 
Rnotaria said:
This was just an example I thought of ...
It's still a homework problem - the Homework Forums are for all such problems, whether they came to you as part of formal classwork or as self-study.

I am closing this thread, but I encourage you to start a new thread in the "Introductory Physics Homework" forum and use the template. The process there is designed for this sort of problem.
 

Thread 'Mousetrap Car Energy efficiency'

For simple comparison, I think the same thought process can be followed as a block slides down a hill, - for block down hill, simple starting PE of mgh to final max KE 0.5mv^2 - comparing PE1 to max KE2 would result in finding the work friction did through the process. efficiency is just 100*KE2/PE1. If a mousetrap car travels along a flat surface, a starting PE of 0.5 k th^2 can be measured and maximum velocity of the car can also be measured. If energy efficiency is defined by...
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