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# need to clarify on newton's 3rd law plz watch

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1. so i saw a question unit 1 GCE may 2015 17 (b)
it required us to explain why holding on to a vertical stand would prevent the passenger falling backwards, so,the answer talked about newton's 3rd law first because as the arm acts on the train the train acts on the arm,3rd law pairs are supposed to be of equal magnitude,im wondering why they said there WAS a resultant force because the passenger was accelerating with the train. Where did the extra force come from? Cause if the forces are of the same magnitude,then why cant we say theyre cancelling out?
2. (Original post by sarah99630)
so i saw a question unit 1 GCE may 2015 17 (b)
it required us to explain why holding on to a vertical stand would prevent the passenger falling backwards, so,the answer talked about newton's 3rd law first because as the arm acts on the train the train acts on the arm,3rd law pairs are supposed to be of equal magnitude,im wondering why they said there WAS a resultant force because the passenger was accelerating with the train. Where did the extra force come from? Cause if the forces are of the same magnitude,then why cant we say theyre cancelling out?
It may be good that you post the whole question or a link. Don't really follow your explanation.

Newton third law pair of forces are equal in magnitudes but opposite in direction. They don't "cancel" each other because the forces are acting on two different bodies.
3. (Original post by Eimmanuel)
It may be good that you post the whole question or a link. Don't really follow your explanation.

Newton third law pair of forces are equal in magnitudes but opposite in direction. They don't "cancel" each other because the forces are acting on two different bodies.
hmm what if its me pushing someone and someone pushes me with the same force, i wouldnt move right? Is that the same case
4. (Original post by sarah99630)
hmm what if its me pushing someone and someone pushes me with the same force, i wouldnt move right? Is that the same case
Not really the same case but have something in common.
5. (Original post by Eimmanuel)
Not really the same case but have something in common.
Oh alright, thank you!

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