Physics Hwk. problem: Conservation of Linear Momentum

[shawonna23]

55 kg swimmer is standing on a stationary 225 kg floating raft. The swimmer then runs off the raft horizontally with a velocity of +4.4 m/s relative to the shore. Find the recoil velocity that the raft would have if there were no friction and resistance due to the water.

I used the equation vf2=-m1*vf1 divided by m2, but the answer is wrong. Did I use the wrong equation? Please Help!

 

[BlackMamba]

Hey I had this same homework problem. Almost exactly infact. The only thing different is your raft weighs 225kg and mine weighed 230kg. And I got the problem correct so I think I can help you.

The equation you are using is correct. What was your answer?

 

[shawonna23]

Physics Hwk. Problem: Conservation of Linear Momentum

Thanks, the answer i got is -1.08.

 

[BlackMamba]

That should be the correct answer then. Unless your using webassign and it requires 3 significant digits. Then you are rounding too soon.