# Weightlessness on a Ferris Wheel

1. Oct 8, 2009

### Sumbhajee

1. The problem statement, all variables and given/known data
How many revolutions per minute would a 15.1 m diameter Ferris wheel need to make for the passengers to feel "weightless" at the topmost point of the trip?

2. Relevant equations

3. The attempt at a solution
I assume this problem has something to do with finding acceleration and converting from there. I have been having a lot of trouble with this problem.

2. Oct 8, 2009

### rl.bhat

What are the things you know about vertical circular motion?

3. Oct 8, 2009

### Sumbhajee

I know that Centripetal acceleration = (velocity)^2/radius

4. Oct 8, 2009

### gamer_x_

If you're weightless at the top, what does that mean? Draw your free body diagram, then figure out which forces are acting where.

5. Oct 8, 2009

### rl.bhat

Can write this in terms of angular velocity?
What happens at the top of the wheel?

6. Oct 8, 2009

### Sumbhajee

If you are weightless at the top you should have mass * gravity acting down and a centripetal force equal to gravity acting up. But how does this information help to discover revolutions per minute?

7. Oct 8, 2009

### Sumbhajee

To set up the equation would I use the following:

9.80=V^2/7.55 and solve for velocity? But how do you convert velocity to revolutions per minute?

8. Oct 8, 2009

### Sumbhajee

I found the answer! Thank you for all the help.