# Homework Help: Banked curves

1. Oct 17, 2009

### pookisantoki

Two cars are traveling at the same speed of 28 m/s on a curve that has a radius of 124 m. Car A has a mass of 1080 kg, and car B has a mass of 1500 kg. Find (a) the magnitude of the centripetal acceleration and (b) the magnitude of the centripetal force for Car A, (c) the magnitude of the centripetal acceleration and (d) the magnitude of the centripetal force for Car B.

I used the formula V=sqrt(rg tan theta)
for part a: v=sqrt(151*9.80 tan theta)
For part b: v=sqrt (115*9.80 tan theta)

But how would i find theta???

2. Oct 17, 2009

### Dick

Why do you think the curve is banked? The centripetal acceleration doesn't depend on the banking angle anyway. What's the centripetal acceleration of an object moving at velocity v on a curve of radius r?

3. Oct 17, 2009

### rl.bhat

In the problem the angle of banking is not given. So assume it as flat.
On the flat curve, the centripetal force is provided by the frictional force.
For car A, what is the frictional force? You know the centripetal force.
Equating them you can find the μs. Using this you can solve the second part.