Angular momentum, colition, conservation

Click For Summary

Homework Help Overview

The discussion revolves around a problem related to angular momentum and conservation principles, specifically in the context of a pole-vaulting exercise. Participants are attempting to analyze the dynamics of a pole as it transitions from linear to rotational motion upon contact with a wall.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are exploring the conservation of angular momentum, questioning how the initial linear momentum of the pole transforms as it begins to rotate. There is a focus on identifying the components of momentum that contribute to angular momentum and what remains after the transition.

Discussion Status

Some participants have provided insights into the mechanics of the problem, discussing the initial conditions and the implications of the pole's motion. There is an ongoing exploration of the relationship between linear and angular momentum, with no explicit consensus reached yet.

Contextual Notes

The original poster has not provided a clear statement of the problem or a translatable form of the question, which may affect the clarity of the discussion. Additionally, there are references to external resources, such as photos, which may not be accessible to all participants.

Fisica
Messages
12
Reaction score
1

Homework Statement



look photo


Homework Equations






The Attempt at a Solution



LOOK THE PHOTO
 

Attachments

  • Problema.PNG
    Problema.PNG
    43.4 KB · Views: 519
  • 1962728_10203264388668481_1416685147_n.jpg
    1962728_10203264388668481_1416685147_n.jpg
    21.6 KB · Views: 516
Last edited:
Physics news on Phys.org
Welcome to PF;
Please show us you best attempt at the problem in order that we know where you need the most help.
It would also help if there was a a translatable form of the question someplace.
 
Ok, wait a minute.. i going to try to resolve and i will post a photo
 
Yeah - I kinda get that it is a pole-vaulting exercize. "Salto Fosbury" translates into English as "Fosbury Flop".
In the model - a pole is set at an angle to the horizontal and travels left-to-right at some constant initial speed u.
When the bottom of the pole is in contact with the bottom of the wall, the horizontal motion stops and the pole rotates about the bottom end.

You've seen that this is a conservation of angular momentum problem - and you seem to have a handle on it.

The pole has length ##l##, mass ##m##, and initial velocity ##\vec v_i=u\hat\imath## (i.e. speed ##u## in the ##+x## direction.)

It has initial linear momentum was ##\vec p_i=mu\hat\imath## ... you follow so far?

Your question appears to be "what happens to this?"
Particularly, what happens to the part that does not turn into angular momentum?

Consider:
The part that turns into angular momentum is the component of the initial momentum that is perpendicular to the pole. ##p_\perp = mu\sin\theta##
... that's the magnitude - but momentum is a vector.

So what is the momentum that is left over?
Which direction does it point in? (A sketch will be enough to see.)
Consider also: Is the pole acted on by a force during the vault?
 
Last edited:

Similar threads

Replies
4
Views
2K
Replies
4
Views
2K
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
Replies
6
Views
4K
  • · Replies 3 ·
Replies
3
Views
2K
Replies
17
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 16 ·
Replies
16
Views
3K