Need help with an angular momentum problem....

In summary, the student is having difficulty understanding the solution to the homework problem. They are new to the site and do not know how to upload an image. They believe they "solved" the problem, but are unsure if they did. They are concerned about whether they did what was required.
  • #1
EngAM
2
0

Homework Statement


I've spent at least 1.5 hours on this problem trying to figure out what i did wrong and I can't find anything. With an exam in two days plus another chapter to go through.

Regardless, here are the problem(6) and answer, as well as my work. Hope you can read it, and the writing on the bottom left in red was just a variation of me using a negative value for m1(B/4) , as oppose to a positive like the right.

Homework Equations

/ work[/B]

problem and answer:

https://imgur.com/a/C440LPp

work:

https://imgur.com/a/A0KP8VU

Thank you very much

Also, I'm new here so i don't know how embed images.

Problems:

20180421_141214.jpg


Left side of board:
20180421_164715.jpg


Right side of board:

20180421_164648.jpg
 

Attachments

  • 20180421_164715.jpg
    20180421_164715.jpg
    42.5 KB · Views: 310
  • 20180421_164648.jpg
    20180421_164648.jpg
    25.8 KB · Views: 406
  • 20180421_141214.jpg
    20180421_141214.jpg
    19.8 KB · Views: 300
Last edited:
Physics news on Phys.org
  • #2
EngAM said:
Also, I'm new here so i don't know how embed images.
Welcome to the PF.

You use the UPLOAD button in the lower right of the Edit window to upload a PDF or JPEG image. Your work is hard to read at that resolution, so you may want to take several pictures closer to your work to make it more clear. Normally we prefer that the work is typed into the PF, using the math symbols under the Sigma ∑ symbol in the toolbar at the top of the Edit window, or using LaTeX (see the tutorial under INFO, Help/How-To at the top of the page).
 
  • #3
berkeman said:
Welcome to the PF.

You use the UPLOAD button in the lower right of the Edit window to upload a PDF or JPEG image. Your work is hard to read at that resolution, so you may want to take several pictures closer to your work to make it more clear. Normally we prefer that the work is typed into the PF, using the math symbols under the Sigma ∑ symbol in the toolbar at the top of the Edit window, or using LaTeX (see the tutorial under INFO, Help/How-To at the top of the page).

Hopefully you can read it now? Sorry, my camera quality is just poor. But like I said, I feel like I "solved" it right conceptually, i feel like it might be somewhere in my work that's wrong. I know there shouldn't be any torque so angular momentum is conserved, which is why I said total initial momentum (I add the momentums of the separate ants together right) is equal to the total final momentum.
 

1. What is angular momentum and why is it important?

Angular momentum is a measure of the rotational motion of an object. It is important because it helps us understand the behavior of rotating objects, such as planets, atoms, and even subatomic particles. It is also a conserved quantity, meaning it stays constant unless acted upon by an external force.

2. How is angular momentum calculated?

Angular momentum (L) is calculated by multiplying the moment of inertia (I) by the angular velocity (ω). This can be represented by the equation L = Iω. The moment of inertia is a measure of an object's resistance to rotational motion, while angular velocity is the rate of change of angular displacement.

3. What are some real-life examples of angular momentum?

There are many examples of angular momentum in our daily lives. Some common examples include the rotation of the Earth, the spinning of a top or gyroscope, the motion of a spinning ice skater, and the movement of a spinning bicycle wheel.

4. How does angular momentum relate to conservation of energy?

Angular momentum is a conserved quantity, meaning it remains constant in a closed system. This is related to the conservation of energy because any change in angular momentum must be balanced by a change in another form of energy, such as kinetic or potential energy.

5. What are some common challenges when solving angular momentum problems?

One common challenge when solving angular momentum problems is correctly identifying the axis of rotation and choosing the appropriate moment of inertia value. Another challenge is understanding the relationship between angular velocity and linear velocity, as they are related but not interchangeable. It is also important to consider any external forces acting on the system and their effect on angular momentum.

Similar threads

  • Engineering and Comp Sci Homework Help
Replies
6
Views
1K
  • Engineering and Comp Sci Homework Help
Replies
5
Views
3K
Replies
13
Views
894
  • Introductory Physics Homework Help
Replies
9
Views
2K
  • Introductory Physics Homework Help
Replies
19
Views
2K
  • Introductory Physics Homework Help
Replies
14
Views
1K
  • Introductory Physics Homework Help
Replies
11
Views
2K
  • Advanced Physics Homework Help
Replies
18
Views
2K
  • Engineering and Comp Sci Homework Help
Replies
1
Views
8K
Back
Top