- #1

RoyalFlush100

- 56

- 2

## Homework Statement

A small 700-g collar

*C*can slide on a semicircular rod which is made to rotate about the vertical

*AB*at a constant rate of 7.5 rad/s. The coefficients of friction are

*μs*= 0.25 and

*μk*= 0.20.

Determine the magnitude of the friction force exerted on the collar immediately after release in the position corresponding to

*θ*= 75 degrees.

Pic attached below

## Homework Equations

F = ma

an = d^2r/dt^2 - r(d

*θ/dt)^2*

## The Attempt at a Solution

I began by determining net acceleration.

a = (0.5 m)(7.5 rad/s)^2 = 28.125 m/s^2 pointed towards the center of the circle.

So the net force is going to equal (0.7 kg)(28.125 m/s^2) = 19.6875 N towards the center of the circle.

But I'm not sure what the FBD would look like in this case. I know that it'll have weight vertically down, but I am not sure how to set up the normal and frictional forces in this instance.