I may have made a mistake in calculating, but I just finished lab homework where my calculated momentum was different before and after an inelastic collsion. Is it possible that momentum was lost in the vibration of the impact or something? The experiment placed two gliders on a level air track (isolated system) and one glider was pushed into a second one that was station. here are my values: m for both gliders = .2014 kg v1i = .3576 m/s (after the push) v2i = 0.000 m/s vf = .0716 m/s with all that subbed into the conservation of momentum equation for inelastic collsions, i got .072 N*s for before the collision, and .028 N*s for after. That doesn't =0!