Momentum                                             m = 5 kg
   A rocket of mass 5 kg is travelling                 u = 200 ms-1
                                        -1
   horizontally with a speed of 200 ms  when it        m = 3 kg
   explodes into two parts.  One part of mass 3          1
                                                       m = m – m  = 5 – 3 = 2 kg
   kg continues in the original direction with a         2           1
   speed of 100 ms-1.  The other part also             v  = 100 ms-1
                                                        1
   continues in this same direction.  Calculate        v  = v
   its speed.                                           2    2
       momentum before the explosion = momentum after the explosion
           mu = m v  + m v
                    1 1     2 2
           (5 x 200) = (3 x 100) + (2 x v )
                                           2
           1000 = 300 + 2v2
           1000 – 300 = 2v2
           700 = 2v2
           v  = 700/2
             2
           v  = 350 ms-1
             2
                                                                                Animated Science
                                                                                       2016
                                                                     D
                                  (mv-mu )/t so kgms-2 
                                  W = mg or F=ma 
            A               Cons of Momentum
                            0 = m v  – m v
                                  1 1   2 2
                                                                            Animated Science
                                                                                  2015
 3
                                                                                    A
                                                              If 100% elastic 
                                                              momentum is passed 
                                                              through to T  so T  
                                                                           2     1
                                                              must be at rest.
                                                              As same mass the 
                                                              velocity is unaltered
                                                                                   Animated Science
                                                                                          2015
          Ft     = mv-mu
          (mv-mu) /F  = t
          mv/F  = t
          584.6 x 10-6
                                                                       A
             p  = momentum = mv
              = m/V 
             V = m 
             p = (V) * v
                             -4   3                  -4     -1                   -1
             v = 2 x 10 m  / 7.2 x 10 ms  = 0.277ms
                             -3                 -4    3                     -1                             -1                         -1
             1000kgm  x 2.0 x 10  m  x   0.277ms =  0.05555 kgms =  0.056 kgms
                                                                                                                                         B