A Vogon’s grandmother, whose mass is 89 kg, drifts through empty space with a velocity of –6.20 m/s until she encounters the 460-kg Ravenous Bugblatter Beast of Traal, drifting with a velocity of +2.80 m/s. When they meet, the RBBoT immediately eats her. What is the beast’s velocity after his snack?
Silly, silly question.
Momentum is conserved.
momentum before=momentum after
89(-6.20)+460(2.80)=(89*460)V