Solving the Balanced Board Problem

  • Thread starter Thread starter splac6996
  • Start date Start date
  • Tags Tags
    Board
Click For Summary

Homework Help Overview

The problem involves two individuals standing on a balanced board, with a focus on the dynamics of their movements when one jumps. The subject area relates to mechanics, specifically the conservation of momentum and angular momentum principles.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the application of conservation laws, questioning whether to use linear or angular momentum. Some suggest that the torque about the pivot is zero, while others explore the relationship between mass, distance, and velocity in their calculations.

Discussion Status

The discussion includes various interpretations of the problem, with some participants offering insights into the use of angular momentum. There is acknowledgment of the complexities involved, particularly regarding external forces and the setup of the problem.

Contextual Notes

Participants note the importance of the distance between the two individuals and the implications of external forces like gravity on the system. There is also mention of specific equations related to angular momentum and the need for careful consideration of variables.

splac6996
Messages
37
Reaction score
0

Homework Statement



Two people are standing on a very light board that is balanced on a fulcrum. The lighter person suddenly jumps straight up at . Just after he jumps, how fast will the heavier person be moving?

Homework Equations


M1*(Vf1) + M2*(Vf2) = M1(Vi1) + M2(Vi2)



The Attempt at a Solution


I tried using this equation but I did not get a likely solution I think I should include the distance that the two man are apart but I do not know what to do with that.
 
Physics news on Phys.org
I believe you need to use conservation of angular momentum about the pivot of the fulcrum... the torque about the pivot is 0... hence the angular momentum isn't changing... we can't use conservation of linear momentum because of the external forces like gravity and the force exerted at the pivot of the fulcrum.
 
so i know the mass of both men and the tangential velocity for one of them so from that point do I set the following equation equal to one another to solve for tangential velocity of the second man.

L(angular momentum)=m*r*v(tangential velocity)
 
Thanks i figured it out using that equation but r should be r^2 for both sides.
 

Similar threads

  • · Replies 10 ·
Replies
10
Views
4K
  • · Replies 21 ·
Replies
21
Views
5K
  • · Replies 9 ·
Replies
9
Views
3K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 13 ·
Replies
13
Views
4K
Replies
4
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K