Angular Momentum tricky problem

Click For Summary
SUMMARY

The discussion centers on a challenging homework problem involving angular momentum, specifically utilizing the parallel axis theorem and angular acceleration. The user attempted to calculate the mass moment of inertia using the equation I0 = I + mr², where I for a slender bar is given as 1/12 * m * L². However, the user failed to incorporate frictional torque and the angle, leading to an incorrect solution. The community emphasizes the importance of showing all calculations for clarity and effective problem-solving.

PREREQUISITES
  • Understanding of angular momentum and torque concepts
  • Familiarity with the parallel axis theorem
  • Knowledge of mass moment of inertia calculations
  • Basic principles of angular acceleration
NEXT STEPS
  • Review the application of the parallel axis theorem in rotational dynamics
  • Learn how to calculate frictional torque in rotational systems
  • Study the relationship between angular acceleration and tangential acceleration
  • Practice solving angular momentum problems with varying complexities
USEFUL FOR

Students in physics or engineering courses, particularly those studying dynamics and rotational motion, will benefit from this discussion. It is also valuable for anyone seeking to improve their problem-solving skills in angular momentum scenarios.

lecammm
Messages
9
Reaction score
0

Homework Statement


As the picture shows, we are given several variables, but I am near completely lost. I am behind in my course and am trying to catch up as best as I can but this problem is really hard for me


Homework Equations



The equations that I have used are;

parallel axis theorem
angular acceleration = tangential acceleration*radius

The Attempt at a Solution


I know that this solution will be completely wrong as I haven't utilised the frictional torque, nor the angle.

So, by applying the parallel axis theorem for the mass moment of inertia;

I0 = I + mr^2
I(slender bar) = 1/12 * m * L^2
∴ I0 = 1/12 * m * L^2 + mr^2

then used the fact that:

ƩM0 = I0:

and therefore:

mgb = I0 * angular acceleration:
where b is the distance from the COM

however, as assumed, this gave the wrong answer, I'm really stuck with it and I want to know how I can do it for problems to come. Thanks! :D
 

Attachments

  • attachment2.png
    attachment2.png
    2.7 KB · Views: 439
Physics news on Phys.org
You need to show your calculations.

Your equation for the sum of the moments = I0 is incomplete.

How are we to know what you've done if you don't provide your work?
 

Similar threads

  • · Replies 17 ·
Replies
17
Views
1K
Replies
335
Views
17K
Replies
5
Views
1K
Replies
17
Views
2K
Replies
3
Views
2K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 45 ·
2
Replies
45
Views
4K
Replies
5
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K