Momentum Changes in a variable mass system.

In summary: I'll be able to use these examples to show how momentum changes with mass and velocity. My teacher said that the concept is a little advanced, but I think I can handle it.In summary, the student is trying to do a presentation on momentum changes in variable mass systems. He has everything done but examples, and needs help understanding the equation. He finds a website that provides two examples of rockets and the fuel used in their deployment. He plans to use those examples to show how momentum changes with mass and velocity.
  • #1
Faustian
2
0
Pleeeease help me. I have to do a twenty minute presentation on momentum changes in variable mass systems. I have everything done but examples. The equation I have is m(t)a=Rv where R is the rate the mass of the rocket is decreasing and v is the velocity of the gas ejected with respect to the rocket. Does anyone have any examples from the internet I can use? At least any realistic variables? I have absolutely NO idea what realistic numbers would be for this situation. Actually, to be honest, I'm not really sure how to use the equation. What would I have to have to solve for a sample? The velocity of the particles ejected, the time and rate of change of the mass? Then I would just use the rate of change and the time to find m(t) and I would solve for a? :frown: This is actually for AP Calculus, but I'm pretty sure this concept is a bit advanced for the high school level (My physics teacher couldn't even help me, which is kind of sad). Please, any help will really be appreciated.
 
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  • #2
Umm… ok. Well, that certainly sounds like an interesting presentation but a lot of work. I hope you're enjoying it.
There is a site by Michael Richmond, Dept. of Physics Rochester Institute of Technology, which should be helpful.
http://spiff.rit.edu/classes/phys311_t/workshops/w10a/rockets/rockets.html [Broken]
It lists two rockets and the fuel used in there deployment. You might have already considered this, but using cars as examples might be simpler, as you don’t have to consider changes in gravity and air density.
 
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  • #3
Thank you. That looks like it'll help. The thing is, most of the people in my calculus class haven't even taken a basic physics class. Because of this, I can make my problems as simple as possible. The samples I use won't even have ANY gravity or air resistance.
 

1. How does the mass of a system affect its momentum?

The mass of a system has a direct effect on its momentum. As the mass increases, the momentum also increases. This is because momentum is directly proportional to mass, meaning that the greater the mass, the greater the momentum.

2. Can momentum change in a variable mass system?

Yes, momentum can change in a variable mass system. This is because momentum depends not only on the mass of the system, but also on its velocity. If the velocity changes, the momentum will also change.

3. Does the direction of the velocity affect the momentum in a variable mass system?

Yes, the direction of the velocity does affect the momentum in a variable mass system. Momentum is a vector quantity, meaning it has both magnitude and direction. Therefore, a change in velocity direction will result in a change in momentum.

4. What is the equation for calculating momentum in a variable mass system?

The equation for calculating momentum in a variable mass system is p = mv, where p is momentum, m is mass, and v is velocity. It is important to note that this equation only applies when the mass is constant. When the mass is changing, a different approach, such as using the impulse-momentum theorem, must be used.

5. Can the momentum of a variable mass system be conserved?

Yes, the momentum of a variable mass system can be conserved. This is known as the law of conservation of momentum, which states that the total momentum of a system remains constant unless acted upon by an external force. In a variable mass system, the mass may change, but as long as there is no external force acting on the system, the total momentum will remain constant.

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