Solving Questions with Variable Mass: Seeking Guidance

In summary, the conversation is about the difficulty of dealing with questions involving variable masses and requesting help on the best approach and examples for solving them. The advice given is to post specific problems on a homework forum for assistance.
  • #1
MMS
148
4
Hello everyone.

I've been struggling with how to deal or solve questions that include variable masses. Considering the method I usually try to solve with, it either gets me lost or just makes things complicated and doesn't work often to me. :P

I was wondering if you guys could help me out and tell me what is the best way to approach questions with variable mass and how to actually solve them. examples would also help a lot.


Thank you!
 
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  • #2
Yes, "examples would help a lot". How about showing one? That is, show a specific problem you are having trouble with.
 
  • #3
One of our homework forums would be the best place to do this, even if it's not an actual assignment for a class. The "homework helpers" are used to helping people find errors and misconceptions.
 
  • #4
Usually, the mass has to go somewhere, so some of the momentum goes with it.
 
  • #5
If m is variable then "F= ma" (force equals mass times acceleration) becomes "[itex]F= \frac{d(mv)}{dt}= ma+ v\frac{dm}{dt}[/itex]".
 
  • #6
First of all thank you all for the replies. As soon as I get troubled again with a problem, I'll make sure to post it here before looking at its solution.
 
  • #7
MMS said:
First of all thank you all for the replies. As soon as I get troubled again with a problem, I'll make sure to post it here before looking at its solution.

Not quite EXACTLY here in Classical Physics, I hope :smile:
Post it to one of our homework forums.
 

1. How do you solve questions with variable mass?

The key to solving questions with variable mass is to use the formula F=ma, where F represents the force, m represents the mass, and a represents the acceleration. By rearranging this formula, you can solve for any of the variables, depending on what information is given in the question.

2. What is the importance of understanding variable mass when solving problems?

Understanding variable mass is crucial in solving physical science problems, as many real-world scenarios involve objects with changing mass. By understanding how mass affects force and acceleration, you can accurately predict and explain the behavior of objects in motion.

3. Can you give an example of a problem that involves variable mass?

One example of a problem that involves variable mass is a rocket launching into space. As the fuel is burned, the mass of the rocket decreases, causing a change in the force and acceleration. By using the formula F=ma, you can calculate the force needed to propel the rocket and the resulting acceleration.

4. Are there any limitations to using the F=ma formula for solving problems with variable mass?

While the F=ma formula is a useful tool for solving problems with variable mass, it does have some limitations. This formula assumes that the mass is constant throughout the motion, which may not always be the case in real-world situations. Additionally, it does not take into account other factors such as air resistance or friction.

5. How can I improve my problem-solving skills when it comes to variable mass?

To improve your problem-solving skills for questions involving variable mass, it is important to practice solving a variety of problems and familiarize yourself with different scenarios. You can also review and understand the underlying principles and concepts, such as Newton's laws of motion and the relationship between force, mass, and acceleration. Additionally, seeking guidance from a teacher or tutor can also be helpful in developing your skills in this area.

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