How Fast Can a Ring with Uneven Mass Distribution Roll Without Hopping?

Click For Summary

Homework Help Overview

The discussion revolves around a physics problem involving a ring with uneven mass distribution and its rolling motion. The original poster presents a scenario where a ring has three attached masses and seeks to determine the maximum velocity required for the ring to roll without hopping off the ground.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the conditions under which the ring might hop off the ground, questioning the criteria for this event and the forces involved. There are inquiries about the upward forces acting on the ring and the implications of the center of mass acceleration.

Discussion Status

The discussion is active, with participants engaging in questioning the assumptions made about the forces at play. Some guidance has been offered regarding the need to clarify the expressions for forces involved in the problem.

Contextual Notes

The problem includes specific constraints related to the mass distribution of the ring and the angles between the attached masses, which may influence the dynamics being analyzed.

C-137
Messages
2
Reaction score
0
Homework Statement
Let there be a ring of mass m and radius r. Let 3 masses be attached to the ring and named as O,P and Q. Mass of O and Q is 2m and mass of p is M. The angle between 2 masses is 15 degrees as shown in the figure.
Find the maximum velocity the ring must roll so that it doesn't hop while rolling i.e. to roll normally (without slipping), not bouncing.
Relevant Equations
Moment of inertia of a ring= mr^2
torque= I*(alpha)
Problem Statement: Let there be a ring of mass m and radius r. Let 3 masses be attached to the ring and named as O,P and Q. Mass of O and Q is 2m and mass of p is M. The angle between 2 masses is 15 degrees as shown in the figure.
Find the maximum velocity the ring must roll so that it doesn't hop while rolling i.e. to roll normally (without slipping), not bouncing.
Relevant Equations: Moment of inertia of a ring= mr^2
torque= I*(alpha)

Tried hard.
 

Attachments

  • Untitled.jpg
    Untitled.jpg
    4 KB · Views: 295
Physics news on Phys.org
Hello Cs, :welcome:
C-137 said:
Tried hard.
That's always good. But not good enough at PF. So post your trials to allow us to assist! What's the criterion for hopping off the ground ? At what point in the rotation would that happen ?
 
I guess when
total upward force + normal reaction >= mg
 
What upward force is there except for normal reaction force ?

And what expressions do you have for these ?
 
C-137 said:
I guess when
total upward force + normal reaction >= mg
You are assuming that leaving the ground means the mass centre of the system is accelerating upwards. If I trip while running, I am likely airborne while accelerating downwards,
 

Similar threads

  • · Replies 42 ·
2
Replies
42
Views
4K
  • · Replies 97 ·
4
Replies
97
Views
6K
  • · Replies 7 ·
Replies
7
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 59 ·
2
Replies
59
Views
5K
  • · Replies 7 ·
Replies
7
Views
3K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
Replies
26
Views
6K
  • · Replies 21 ·
Replies
21
Views
7K