This is the absolute basic of a physics and yet 2 hours of googling fails to find an answer ! So ignoring all vertical movement and just concentrating on the horizontal movement:-
A man who weighs 75 kg jumps off a pier (steps off horizontally) with a force of 150N. Ignoring gravity he accelerates by 2 meters per sec per sec.
A man who weighs 75kg jumps off (steps off horizontally) a boat that weighs 75 kg with a force of 150N. Ignoring gravity he accelerates by 2 meters per sec per sec. So does the boat (it accelerates by same amount), but in the opposite direction.
What is wrong here? Im sure the boat and the man would end up at half the speed in each direction compared to example 1. Example 2 sounds like free energy compared to example one. What am I missing, apart from a working version of google, and an easy way to format this text?
p.s. I think one of my key confusions is in example 2, is the acceleration relative to a point in space or is the acceleration relative to the other body. I.e. do they accelerate away from each other at 2m per sec^2 or 4m per sec^2? I guess my other confusion is if they are accelerating away at twice the rate then I appear to be doing twice the amount of work for the same amount of force applied which seems odd, and feels like free energy.