# Homework Help: Uniform cicrcular motion problem

1. May 27, 2006

### mikejones2000

Uniform cicrcular motion problem...plz help..

I am currently having an incredibly difficult time on the following homework problem dealing with circular motion. The problem is as follows:

The fast French train known as the TGV (Train à Grande Vitesse) has a scheduled average speed of 216 km/h.

(a) If the train goes around a curve at that speed and the acceleration experienced by the passengers is to be limited to 0.045g, what is the smallest radius of curvature for the track that can be tolerated?
(b) At what speed must the train go around a curve with a 1.70 km radius to be at the acceleration limit?

I converted the speed to m/s and tried using a=vsq./r, but keep screwing up, any help would be greatly appreciated!

2. May 27, 2006

### Hootenanny

Staff Emeritus
Hi mike, welcome to PF.

I can't see a problem here, perhaps if you show your working we can point out what you are doing wrong. Remember to multiply 0.045 by 9.81 to obtain the centripetal acceleration.

~H

3. May 27, 2006

### al_201314

Centripetal Acceleration can also be written as v^2/r.

4. May 28, 2006

### Hootenanny

Staff Emeritus
The OP knows this and stated it in his original post;

~H