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Im having a real hard time understanding how newtons third law works.

Say im accelerating a 1kg ball to 50m/s^2. This means that im applying a force of 50N on the ball.

Newtons third law tells us that every reaction has an equal but opposite reaction.

My hand is getting the 50N back because my hand has accelerated the ball.

But my hand is already moving with a force of 50N meaning that my hand would just stop moving and nothing else.

But if you were to be in vacuum your body would start moving with a force of 50N in the opposite direction right?

This doesnt make sense to me because the 50N reaction force cancels out the 50N force of my hand and therefore there wont be a 50N force on the rest of my body.

So how do I start moving in the opposite direction?

Qmechanic
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b0red
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    Does this answer your question? Given Newton's third law, why are things capable of moving? – Dale Jul 25 '21 at 21:58
  • The short answer is the action-reaction pair of forces per Newton's 3rd law don't "cancel" (a common misunderstanding). You have to apply Newton's 2nd law to the ball and you individually. – Bob D Jul 25 '21 at 22:14
  • I know the ball start moving, but in order to accelerate the ball my hand is being accelerated by my muscles and as soon as my hand hits the ball, the energy is given to the ball(action) and my hand stops moving(reaction). But then the reaction force was used to stop my hand from moving and not to accelerate the rest of my body so how do I start moving – b0red Jul 26 '21 at 10:03

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