# Plot motion of particle with constant speed and angular velocity

Consider the problem of a particle sliding inwards with a constant speed c and starting at radius R=pc/Ω, on a platform rotating with a constant angular velocity Ω. Give a plot of the trajectory of the particle from r=R to r=0, for p=0.5, 1, 2, 6.

I'm a little confused on how to do this. If there is no acceleration, then would the plot just be a series of straight lines? And should I plot r vs t even though time isn't mentioned at all?

## Answers and Replies

"Sliding" would imply that there is no friction with the platform, in which case the trajectory should indeed be a straight line - in an inertial frame of reference. Are you perhaps supposed to find the trajectory in the platform's frame?

Also, how can something slide inward if it's moving in circular motion? Wouldn't centripetal force cause it to slide outward?

Also, how can something slide inward if it's moving in circular motion? Wouldn't centripetal force cause it to slide outward?

That's why I think there is no friction.