question_answer 18)

A shell of mass 0.02 kg is fired by a gun of mass 100 kg. If the muzzle speed of the shell  what is the recoil speed of the gun ?                                          

Answer:

Mass of shell,    m = 0.02 kg                        Mass of gun,     M = 100 kg                        Speed of shell,                            Let V be the recoil speed of the gun. According to the law of conservation of momentum,                        Initial momentum = Final momentum             or                          Negative sign indicates that the gun moves backward as the bullet moves forward.