- #1

lc99

- 161

- 3

## Homework Statement

A phonograph record is whiring around at 103 rpm. Two balls of mass 1 kg are sitting on the disk and are at rest with respect to disk. The first ball (1) sits at a radius 5 away from center. The second ball (2) sits at a radius of 10 away from center. What is the ratio of friction forces acting on them? Ratio = (Friction of 1/Friction of 2)

A)0.5

B) 1

C) 2

D) .25

E) not enough info

## Homework Equations

T = Ialpha

## The Attempt at a Solution

Okay, first,

I know that the disk is rotating at a constant velocity. This means that angular acceleration is 0, thus, the Torque is 0. If the torque is 0 for this disk that is rotating constantly, then that means that net torque is 0 because friction is acting on the balls. Therefore, some force is oppose this friction for net torque to be 0.

However, this doesn't really help me because Torque is just 0? I'm thinking the answer is either E) or could be B) or C) if I am thinking wrong