MOMENTUM

measured in Ns

 

Momentum is the effect of a moving mass.  The amount of momentum of an object is dependant on its mass and its velocity.  So a large, heavy man running slowly can have the same momentum as a small, light man running very fast!

 

 

mom = mv

 

Conservation of Momentum

 

Momentum is conserved before and after any collision

 

ie. Total momentum after   =  Total momentum before

 

 

When doing these questions, it is VITAL to have a diagram showing before and after velocities

 

eg.        20m/s                 10m/s

Before                                      

 

                                         

                                                    

 

After                                        

            10m/s                  Vm/s

 

So

Mom Before = Mom After

 

      

               

                     

                       

                       

 

Impulse

 

Measured in Ns

 

Impulse can be defined in 2 ways:

1.      Impulse = change of momentum of a

                                    particle

 

 

NB: The impulse of A on B has to be the same as the impulse of B on A.  So, when using I = mv  mu, remember to only use one particle

 

2.      When a force (F) acts on a particle for a length of time (t) it produces a change of momentum (eg. A cricket ball hitting a bat)

 

So impulse  

 

 

Therefore