# Centripetal Force (RPM Question)

• McKeavey

## Homework Statement

A coin is placed 18cm from the axis of a rotating turntable of variable speeds. If the coefficient of friction is 0.68, what is the maximum r.p.m that the coin can handle before sliding off?

## Homework Equations

This is basically what I need..
I know there's mv^2/r
But which equation do I need for RPM questions?

## The Attempt at a Solution

None at the moment, not sure of the equation I'm supposed to use :S

McKeavey said:

## Homework Statement

A coin is placed 18cm from the axis of a rotating turntable of variable speeds. If the coefficient of friction is 0.68, what is the maximum r.p.m that the coin can handle before sliding off?

## Homework Equations

This is basically what I need..
I know there's mv^2/r
But which equation do I need for RPM questions?

## The Attempt at a Solution

None at the moment, not sure of the equation I'm supposed to use :S

As well as mv2/r there is 4∏2rm/T2 where T = period

Since frequency is 1/T that would mean 4∏2rmf2

frequency means revolutions per second. r.p.m is revolutions per minute.