How Do Newton's Third Law and Force Calculations Apply to Hockey Players on Ice?

Click For Summary

Homework Help Overview

The discussion revolves around the application of Newton's Third Law and force calculations in the context of two hockey players on ice. The original poster presents a scenario where Player A and Player B exert forces on each other, raising questions about action/reaction forces and resulting accelerations.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants explore the action/reaction forces between the players and question the interpretation of the forces applied by each player. There is discussion about how to account for the forces acting on each player and the resulting accelerations.

Discussion Status

Some participants are seeking clarification on the correctness of their interpretations and calculations regarding the forces and accelerations. There is a mix of opinions on how to approach the problem, with some suggesting that the forces should be equal in magnitude due to Newton's Third Law, while others question the setup of the problem.

Contextual Notes

There are indications of confusion regarding the nature of the forces applied by the players, with some participants noting that the question may be poorly framed. The discussion also touches on the implications of the players being extended bodies and how that affects the forces they exert on each other.

VidsEpic
Messages
10
Reaction score
0

Homework Statement



two hockey players are standing on ice. Player A is 100kg and player B is 112kg, Player A pushes B with 40N and player B pushes A with 50N.

what are the action/reaction forces?
what are the accelerations?

Homework Equations



F = ma

The Attempt at a Solution



player A has a force of 50N on him plus the reaction from his own force of 40N making 90N left

90N on each player in opposite directions, 90/100 = 0.9 m/s^2 and 90 /112 = 0.8 m/s ^2 in other direcctionPlease help me!
 
Physics news on Phys.org
VidsEpic said:

Homework Statement



two hockey players are standing on ice. Player A is 100kg and player B is 112kg, Player A pushes B with 40N and player B pushes A with 50N.

what are the action/reaction forces?
what are the accelerations?


Homework Equations



F = ma


The Attempt at a Solution



player A has a force of 50N on him plus the reaction from his own force of 40N making 90N left

90N on each player in opposite directions, 90/100 = 0.9 m/s^2 and 90 /112 = 0.8 m/s ^2 in other direcction


Please help me!
Looks fine.
Where do you need help?
 
Is this correct?
 
The diagram looks like this:http://i.imgur.com/LP6NfNw.jpgsome people are telling me that it is 10N left on the 100kg object?

Is it correct that I consider on each object the force of its own reaction + the force applied to it so that on 100kg I have 90N left and on 112kg I have 90N right?
 
VidsEpic said:
Is it correct that I consider on each object the force of its own reaction + the force applied to it so that on 100kg I have 90N left and on 112kg I have 90N right?
I would interpret the problem statement in that way, yes.

Please don't write PMs related to homework threads, they are just annoying.
 
VidsEpic said:

Homework Statement



two hockey players are standing on ice. Player A is 100kg and player B is 112kg, Player A pushes B with 40N and player B pushes A with 50N.
This is a poor question, in my view. What does it mean that A applies 40 N of force to B and B applies 50 N to A? How? They will always apply the same magnitude of force to each other - even if one pushes harder than the other.

AM
 
The players are extended bodies, and push each other at different points. See picture.

ehild
 

Attachments

  • pushing.JPG
    pushing.JPG
    5.6 KB · Views: 485
ehild said:
The players are extended bodies, and push each other at different points. See picture.

ehild
Ok. But that does not mean that they push each other with different magnitudes of force.

An astronaut in space may push off with his legs against one end of the spaceship with 100 N force. But that does not mean that the spaceship applies 0 force to the astronaut. On the contrary, the spaceship applies 100N of force to the astronaut. There is no difference between "apply" and "push" here.

AM
 

Similar threads

Replies
6
Views
2K
  • · Replies 11 ·
Replies
11
Views
3K
Replies
7
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 2 ·
Replies
2
Views
4K
Replies
4
Views
2K
  • · Replies 2 ·
Replies
2
Views
6K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 2 ·
Replies
2
Views
5K
  • · Replies 2 ·
Replies
2
Views
14K