Question

If you get a negative impulse, does this mean you lost momentum? I know Impulse=change in momentum. Ex) A ball hits a wall and leaves the wall with a lower velocity than when it hit. Is momentum conserved?

Answer 1

If you get a negative impulse, does this mean you lost momentum? I know Impulse=change in momentum

Impulse is basically the impact of force or change in momentum. It is taken negative depend upon the situation given to you. For example If a ball is throw with momentum P towards the wall and the ball comes to rest after collision then the impulse due to wall on ball is taken as negative because change in momentum is negative. Also the force that wall applied to ball is in opposite directions to the direction of momentum. Impulse=F t . if taken left side as negative then by convention force by wall is negative direction therefore impulse is in negative direction we put -I instead of +I. In general the negative and positive of physical quantity all depend upon the vectors and sign convention.

A ball hits a wall and leaves the wall with a lower velocity than when it hit. Is momentum conserved?No, momentum is not conserved in this case because momentum depends on velocity. Since velocity of ball is decreased, momentum is not conserved.