Newtons Third Law: Cause/Effect or Simultaneous?

In summary, the conversation discusses the concept of force and its effects on objects during collisions. It explores the questions of whether a stationary object expands or compresses when hit by a moving object, and if a transfer of energy or a change in direction occurs between colliding objects. The concept of non-linear force propagation is also brought up, as well as the role of intermolecular forces in distributing momentum during collisions. The conversation ends with a discussion about the relationship between mass, velocity, and displacement in collisions.
  • #1
omin
187
1
When object A and object B collide, where A is moving and B is stationary and where B seems to compress:

Does B expand in response because a pre-existing internal force exists in B and exerts an equal and opposite reaction, or

Is the entity motion transferred from A to B redirected back at A from B the equal and opposite force in return?

If A and B were the exact mass and had a collinear collision and both went in equal and opposite directions, is this proof of internal forces that change the direction or a transfer of the entity motion?

If A causes B to accelerate after the collision, is:
1. the force of B exactly the same as before
2. the force of B the same as before, but more force because of the new velocity, or
3. the same force as before, but the new velocity is a new shape of the same medium in which the same value of force is expressed?

I'll take any response.
 
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  • #2
I have no idea what you are saying, but I'll state the third law in simple terms.

Whenever a force is acted on B by A, a force equal in magnitude and opposite in direction is acted on A by B simultaneously.

Consequences:
1. Forces must work in pairs. It's impossible for any force to exist on it's own.
2. The action-reaction pairs must act on different objects, in different directions.

Did it help?
 
  • #3
Let me try again.

Assumption #1 I assume when an object accelerates, the object that it contacts is imparted with some 'physical entity' to it to make it move faster.

Assumption #2 I also assume 'no physical entity' is imparted, and that no object has has anything extra because it's moving faster or has anything less because it's moving slower.

After a baseball is hit, the baseball flys away from the bat because of energy given to it by the bat or the base ball accelerates because it's own equal and opposite energy is repsonding to itself?
 
  • #4
omin said:
When object A and object B collide, where A is moving and B is stationary and where B seems to compress:

Does B expand in response because a pre-existing internal force exists in B and exerts an equal and opposite reaction, or

Is the entity motion transferred from A to B redirected back at A from B the equal and opposite force in return?

If A and B were the exact mass and had a collinear collision and both went in equal and opposite directions, is this proof of internal forces that change the direction or a transfer of the entity motion?

If A causes B to accelerate after the collision, is:
1. the force of B exactly the same as before
2. the force of B the same as before, but more force because of the new velocity, or
3. the same force as before, but the new velocity is a new shape of the same medium in which the same value of force is expressed?

I'll take any response.


What you are asking may seem simple but it is, in reality, extremely complicated.
The following is not an answer to your question but a general comment of the subject matter.

You question(s) bring to mind the concept of non-linear force propagation, meaning that a shock wave does not behave the same as a linear "push"
A gentle "push" of one object to another obey's classical linear laws of force transfer. However, a sudden impact does not.
The force propagation of a sudden impact is not linear, it is spherically expressed, and it's effects are not well understood.
 
  • #5
First, we must remember that in most of the experiments that we do, we assume the objects to be perfectly rigid, which is not the case in this one. The ball is compressed when being hit.
Okay, back on topic. This is only a gues though, so feel free to correct it if you find anything wrong. The bat hits the ball. A lot of momentum is transferred to the ball. However, since only part of the ball is in contact of the bat, the other part has not yet felt a force to move forward(away from the bat). So, the part that touches the bat collides into the part that doesn't touch, and this causes the ball to be compressed. The momentum is then quickly distributed over the ball by the intermolecular forces within the ball, and soon every part of the ball is moving forward with the same velocity. The ball is hence expanded back into it's original shape and zooms away.
So it's a transfer of energy from the bat, to "some of the ball's particles", and then "all of the ball's particles". The ball itself cannot "create energy", but it helps transfer momentum to "un-moving" particles to help create motion. Otherwise, the ball would tear apart.
 
  • #6
kuenmao said:
The momentum is then quickly distributed over the ball by the intermolecular forces within the ball...
...it's a transfer of energy from the bat, to "some of the ball's particles", and then "all of the ball's particles". The ball itself cannot "create energy"...

If I accelerate something and the mass of that thing is constant before and after the collision creating the acceleration, is an increase in velocity equivalent to a positive thing I am adding to the accelerated object's mass?

Displacement of mass is obvious to everyone. Everyone has seen things move. But if the mass is constant before and after a collision and the velocity increase is proportionately to a decrease betweeen two colliding objects, isn't this displacement of velocity? Isn't velocity being displaced? All things of the physical world I sense are positive. Isn't then velocity a positive entity? What postive thing does velocity represent?
 
  • #7
I'm not sure what you're talking about. Perhaps you should as someone else...
 

What is Newton's Third Law?

Newton's Third Law, also known as the Law of Action and Reaction, states that for every action, there is an equal and opposite reaction. This means that whenever an object exerts a force on another object, the second object exerts an equal force in the opposite direction.

What is the cause and effect relationship in Newton's Third Law?

The cause and effect relationship in Newton's Third Law is that the action is the cause and the reaction is the effect. This means that the force exerted by one object causes the force exerted by the other object in the opposite direction.

Is the reaction in Newton's Third Law simultaneous with the action?

Yes, the reaction in Newton's Third Law is simultaneous with the action. This means that the reaction occurs at the same time as the action, and they are equal in magnitude and opposite in direction.

Can the action and reaction forces be of different magnitudes?

Yes, the action and reaction forces can be of different magnitudes. As long as they are equal in magnitude and opposite in direction, Newton's Third Law still applies.

How does Newton's Third Law apply to everyday situations?

Newton's Third Law applies to many everyday situations, such as walking, throwing a ball, or even sitting in a chair. When we walk, we push against the ground with our feet, and the ground pushes back with an equal force, propelling us forward. When we throw a ball, our hand exerts a force on the ball, and the ball exerts an equal force back, causing it to move. When we sit in a chair, our weight pushes down on the chair, and the chair pushes back with an equal force, keeping us stable.

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