# Difference between Newton's 2nd Law/3rd Law of motion?

#### jakeginobi

1. The problem statement, all variables and given/known dat
What is the difference between Newton's 2nd and 3rd law of motion? Are they related as in if I applied force so that an object accelerates, would it exert the same amount of force towards me?
2. Relevant equations
F=ma

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Yes, they would.

#### jakeginobi

I can't differentiate which law (best choice) to put on a test, cause I'm confused about the 2nd law and 3rd.
For instance, a rocket up in the air - would the best choice be law 2 or 3?

#### andrewkirk

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Both are needed for a rocket to fly. Which is the correct answer will depend on what the question is.

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