Calculating Masses from Fnet: What Am I Missing?

  • Thread starter JoeyBob
  • Start date
  • Tags
    Second law
In summary, the conversation discusses the difficulty in relating the two masses and the use of Fnet=ma to solve for T and find the ratio of m1/m2. The answer is 2.32.
  • #1
JoeyBob
256
29
Homework Statement
See attachwed
Relevant Equations
Fnet=ma, a1=-a2
The answer is supposed to be 2.32.

I've been trying to relate the two masses but am having troubles with it. Fnet for mass one would be m1a. Fnet for mass 2 would be -m2a.
The Fnets would be different though.

m2=-Fnet/a for mass two and m1=Fnet/a for mass one. I can't just divide m2 by m1 because the Fnets are different. Even if they did cancel, the ratio would just be 1 from it.

What am I missing here?
 

Attachments

  • Question.PNG
    Question.PNG
    8.5 KB · Views: 93
Physics news on Phys.org
  • #2
JoeyBob said:
Homework Statement:: See attachwed
Relevant Equations:: Fnet=ma, a1=-a2

The answer is supposed to be 2.32.

I've been trying to relate the two masses but am having troubles with it. Fnet for mass one would be m1a. Fnet for mass 2 would be -m2a.
The Fnets would be different though.

m2=-Fnet/a for mass two and m1=Fnet/a for mass one. I can't just divide m2 by m1 because the Fnets are different. Even if they did cancel, the ratio would just be 1 from it.

What am I missing here?
Nothing is attached.
 
  • Like
Likes JoeyBob
  • #3
Chestermiller said:
Nothing is attached.

Thanks. I think I just figured it out.

m1a=m1g-T and m2a=T-m2g. Solve for T and then subsitute into another equation. You can then do some algebra and get m1/m2=(-a-g)/(a-g).
 

1. What is Fnet?

Fnet, also known as the net force, is the sum of all the forces acting on an object.

2. How do I calculate mass from Fnet?

To calculate mass from Fnet, you will need to use the equation Fnet = ma, where Fnet is the net force, m is the mass, and a is the acceleration. Rearrange the equation to solve for mass: m = Fnet/a.

3. What units should I use when calculating mass from Fnet?

The units for Fnet are typically in Newtons (N), while the units for acceleration are usually in meters per second squared (m/s^2). Therefore, the unit for mass will be in kilograms (kg) when using the equation m = Fnet/a.

4. Can I use this equation for any object?

Yes, the equation m = Fnet/a can be used for any object as long as you have the net force and acceleration values. However, keep in mind that this equation only works for objects with constant acceleration.

5. What other factors should I consider when calculating mass from Fnet?

In addition to net force and acceleration, you should also consider the direction of the forces and the direction of the acceleration when using the equation m = Fnet/a. Make sure to use positive and negative signs to indicate the direction of the forces and acceleration in your calculations.

Similar threads

  • Introductory Physics Homework Help
Replies
7
Views
2K
  • Introductory Physics Homework Help
Replies
17
Views
728
  • Introductory Physics Homework Help
Replies
10
Views
2K
  • Introductory Physics Homework Help
Replies
5
Views
1K
  • Introductory Physics Homework Help
Replies
5
Views
4K
  • Introductory Physics Homework Help
Replies
9
Views
2K
  • Introductory Physics Homework Help
Replies
6
Views
4K
  • Introductory Physics Homework Help
Replies
1
Views
2K
  • Introductory Physics Homework Help
Replies
19
Views
530
  • Introductory Physics Homework Help
Replies
4
Views
881
Back
Top