Posted by Micheal on .
An 80 kg person decides to jump off the back end of a 30 kg canoe. His friend measures the speed of the canoe after he jumps to be 0.8 m/s. The canoe was initially at rest. What rule would I use to find the speed of the person who jumped?

Science 
Steve,
initially there was 0 momentum. That momentum is conserved. So, assigning the canoe's direction as negative,
30*(.8) + 80*v = 0
80v = 24
v = +.3m/s 
Science 
bobpursley,
conservation of momentum
initial mometum= final momentum
(80+30)Vc=30*.880*V
but Vc=0, the canoe was not moving initially. Solve for V