# Homework Help: Centripetal Force and maximum speed

1. Nov 24, 2005

### kingyof2thejring

A motorcyclist is approaching a hump-backed bridge, as shown in the diagram. The bridge forms part of a circle of radius r = 14.4 m. The combined mass of the motorcycle and rider is 141 kg. Calculate the maximum speed in m s-1 at which the rider could travel without leaving the road at the top of the bridge.

How do i go about workin this one out without knowing Fmax and [tex]u\mu[\tex] coeff static friction. Thanks in advance

2. Nov 24, 2005

### mezarashi

If it's not given, I guess you get the pleasure of assuming that it is negligible.

Apply conservation of energy: kinetic energy will be less at the top of the hump.

Check if the velocity is less than which is required for circular motion.

3. Nov 24, 2005

### Päällikkö

What is the force keeping him on the road? It's not friction.

EDIT: Just seconds slower than mezarashi

Last edited: Nov 24, 2005
4. Nov 24, 2005

### kingyof2thejring

so mgh=0.5mv^2
and v=16.8

5. Nov 24, 2005

### mezarashi

Sorries! >.<

6. Nov 24, 2005

### mezarashi

You have the car coming at a certain velocity. Apply the conservation equation.

KE1 + PE1 = KE2 + PE2

The potential PE1 is zero, we consider ground. The potential at PE2 is mgh. We know KE1, find KE2. Use KE2 in your next step.

7. Nov 26, 2005

### kingyof2thejring

cheers mate mezarashi
its best to consider the moition using that equation