Homework Help: Perfectly Inelastic Problem?

1. Apr 17, 2013

physicslover11

1. The problem statement, all variables and given/known data
A block of mass m slides along a frictionless track with speed vm. It collides with a stationarty block of mass M. Find an expression for the minimum value of vm that will allow the second block to circle the loop the loop without falling off if the collision is perfect inelastic.

2. Relevant equations
Uinitial+Kinitial=Ufinal+Kfinal
U=mgh
K=1/2mv^2

3. The attempt at a solution
Since this is a frictionless track, there is no initial kinetic energy, but that is all i really can figure out i am completely lost someone please help!

Attached Files:

• Screen shot 2013-04-17 at 11.23.05 AM.png
File size:
7.8 KB
Views:
973
Last edited: Apr 17, 2013
2. Apr 17, 2013

Staff: Mentor

It is easier to consider this problem backwards: At the top of the loop, the masses are supposed to stay in their track. Which forces act on them? How can they stay in the track, and which velocity do they need?

The masses come from the bottom of the loop. What was their velocity there?

And afterwards, consider the collision.