Centripetal Force on Ferris Wheels

[monicaacinom]

Homework Statement

A roller-coaster vehicle has a mass of 510 kg when fully loaded with passengers (Fig. P7.28).
http://www.webassign.net/sf/p7_28.gif
(b) What is the maximum speed the vehicle can have at point B in order for gravity to hold it on the track?

Homework Equations

F-centripetal = mv^2/R
A-centripetal = V^2/R

The Attempt at a Solution

I tried doing mv^2/R = mv^2/R (there was a velocity given in another part of the problem) but that didn't work.

 

[Doc Al]

I tried doing mv^2/R = mv^2/R (there was a velocity given in another part of the problem) but that didn't work.

The maximum speed at point B has nothing to do with any other speed given in the problem--it is a property of the curvature at point B. To find the condition for maximum speed, analyze the forces on the coaster at point B and apply Newton's 2nd law and what you know about centripetal acceleration.