# Motion of a particle in a rotating tube.

**1. The problem statement, all variables and given/known data**

Hello everyone,

How do I go about this problem; Describe the motion of the particle, m, inside the rotating tube. (See attachment please.)

At time [itex]t=0, r(t=0)=b[/itex] and [itex]\dot{r}(t=0)=v_{0}[/itex]

**2. Relevant equations**

I think it would be practical to use polar coordinates to describe the system.

Then maybe find the kinetic energy and the potential, to find the Lagrangian?

**3. The attempt at a solution**

I don’t really know where to start, any hints or tips are really appreciated.

In class we just started with holonomic constraints, therefore I’m a little new to this concept. I guess it has something to do with this problem?

http://ift.tt/1pmi58y