How do action reaction force pairs arise?


by echolett
Tags: action, arise, force, pairs, reaction
echolett
echolett is offline
#1
Mar28-10, 09:53 PM
P: 1
Hi guys,

What is the reason for action-reaction force pairs to arise?
Is it a consequence of electrostatic repulsion due to interaction of the 2 bodies, or can it be explained using energy conservation or momentum conservation.

Thanks!
Phys.Org News Partner Physics news on Phys.org
Physicists design quantum switches which can be activated by single photons
'Dressed' laser aimed at clouds may be key to inducing rain, lightning
Higher-order nonlinear optical processes observed using the SACLA X-ray free-electron laser
rcgldr
rcgldr is offline
#2
Mar29-10, 05:02 AM
HW Helper
P: 6,925
Quote Quote by echolett View Post
What is the reason for action-reaction force pairs to arise?
It's an axiom or postulate that is just assumed to be self-evident and true. I'm not sure there's a way to prove it. Almost all forces invoved some type of reaction if you look at a situation from a large enough scale, and consider things like how much the earth is affected by a car acclerating on it's surface.

In some cases, a Newton 3rd law pair doesn't require physical contact, such as gravity, where the third law pair is the equal and opposing attractive force on each body in a two body system.
0xDEADBEEF
0xDEADBEEF is offline
#3
Mar29-10, 03:08 PM
P: 824
You could derive force pairs from momentum conservation of arbitrary pairs of objects, but we tend to think of actio = reactio as being more fundamental.


Register to reply

Related Discussions
Gravitational force: action and reaction General Physics 1
Ampère force law, action, reaction Classical Physics 5
forces, action and reaction pairs Introductory Physics Homework 6
Action-Reaction pairs... :( Introductory Physics Homework 18
Action/reaction force in relation to Newton's 3 law Introductory Physics Homework 2