Roller Coaster Friction Problem

[alexcc17]

Homework Statement

A roller coaster begins with a 90m hill followed by a 40m diameter loop. Unfortunately, the coaster hits a 20m long rough patch between the bottom of the hill and the loop. If the friction on the rough patch is .8, then can a roller coaster make it through the loop?

Homework Equations

The Attempt at a Solution

I found that the centripetal acceleration is 9G's and that the weight a person would feel would be 10G's, but I don't know the equation I would use and how to factor in friction.

 

[azizlwl]

The concept of the problem is about conservation of energy.
Taking ground as zero reference of PE.
PE at 90m surely can make a loop of height 90m.
You have to calculate if the extra energy going for 40m loop is exceeding the energy use by frictional force for the given distance.

 

[alexcc17]

Do you know the equation?

 

[PhanthomJay]

That's quite a coaster you got there with 10 g's at the bottom of the loop...without friction. Are you familiar with work-energy methods and minimum speed required at the top of the loop to make it through the loop?

 

[alexcc17]

Afraid not