Shouldn't force pairs equal in magnitude cancel each other?

In summary, the conversation is about Newton's Third Law and how it explains that every action has an equal and opposite reaction. The question is raised about how anything can happen if force pairs always cancel each other out. It is clarified that Newton's Third Law applies to forces acting on different objects, and not on the same object. The importance of drawing separate free body diagrams for each object is also mentioned.
  • #1
Varun Narayanan
3
0

Homework Statement


If every action has an equivalent and opposite reaction, how is that anything ever happens ?. Shouldn't force pairs equal in magnitude cancel each other?

Homework Equations

The Attempt at a Solution


I tried drawing a free body diagram, but it didn't help much. This is a conceptual problem for me
 
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  • #2
Hi!
Could you state Newton's Third Law?
 
  • #3
LemmeThink said:
Hi!
Could you state Newton's Third Law?
Every action has an equal and opposite reaction.
 
  • #5
Varun Narayanan said:
Shouldn't force pairs equal in magnitude cancel each other?
Two forces can cancel each other only if they are acting on the same body. Is that the case with Newton's 3rd law?
 
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Likes CWatters
  • #6
Varun Narayanan said:
Every action has an equal and opposite reaction.
On what object (or objects) are those two forces acting on?
 
  • #7
Have you drawn a free body diagram for each body separately, showing only the forces acting on each body separately?
 

1. Why do force pairs equal in magnitude?

According to Newton's Third Law of Motion, for every action, there is an equal and opposite reaction. This means that when one object exerts a force on another object, the second object will exert an equal but opposite force on the first object.

2. How do force pairs cancel each other?

Force pairs cancel each other out because they act in opposite directions. This means that the net force on an object is zero, resulting in no change in motion.

3. Is it always necessary for force pairs to equal in magnitude?

Yes, according to Newton's Third Law, force pairs must always be equal in magnitude. If the forces were not equal, there would be an unbalanced force, resulting in a change in motion.

4. Can force pairs be equal but act in different directions?

Yes, force pairs can be equal in magnitude but act in different directions. This is because they still follow Newton's Third Law, where the forces are equal and opposite, even if they are acting in different directions.

5. What would happen if force pairs did not cancel each other out?

If force pairs did not cancel each other out and there was an unbalanced force, the object would experience a change in motion. This could result in acceleration, deceleration, or a change in direction.

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