If every action has an equal and opposite reaction, why doesn't it all just cancel out to a net zero outcome?

Answer 1

Because everything will come to zero finally.

Answer 2

That's a great question. It's actually more difficult to answer than I thought when I started.

Let's say you have an object (A) in space that is in motion, and another object (B) not in motion. When object (A) collides with object (B) it transfers what is called kinetic energy to it. kinetic energy is equal to 1/2 the mass of the object times its velocity squared. Energy is always conserved, meaning the same amount of kinetic energy has to be in object B after the collision as object A before. So if they're both the same mass, object A will stop and object B will keep going.

Some energy gets lost as heat in the collision, so the velocity will be slightly less.

But if object B is smaller, it will not be able to absorb all the kinetic energy, so now both objects are still moving in the same direction.

So why doesn't energy just keep dissipating into heat and then nothing else can move any more?

Mass can be converted into energy according to Einstein's theory of relativity which states:
Change in Energy = Change in Mass x Speed of light squared

These are the types of reactions that happen in our sun, and in many other places in the universe. They convert mass into energy, so new energy is available to use.

The amount of energy and mass in the entire universe remains constant, so no new energy or mass is ever created or destroyed, it only changes form.

Hope this helps.

Craig

Answer 3

I think this is because the reaction is effected by another 'body' so it creates a reaction but not to itself (otherwise it would cancel out to zero). With Newton's laws of motion the force of a mass creates an opposite reaction but upon another mass so it still creates motion (eternal motion) but it does not cancel out because the opposite force of reaction is not to the same mass. I hope you understand and I hope I am right.

Answer 4

Because there is the Law of Conservation of Mass or Energy or Inertia etc.
If we are going to cancel out, net zero. No mass, energy etc. anymore. So it has to follow the law.

Answer 5

Newtons law of motion describes how energy (of propulsion) will be distributed. (e.g. half to the boat, half to the water)

It in no way contradicts the first law of Thermodynamics:

"Energy can neither be created or destroyed. It merely changes forms."

Newtons second law affirms Thermos first law.

An object in motion will remain in motion until an outside force absorbs or redirects it's energy.

Answer 6

and how do YOU know that it doesn't, in the end??