- #1

- 48

- 0

## Homework Statement

A wheel, mounted on a vertical shaft of negligible rotational inertia, is rotating at 500 rpm (CCW from above).

Part a) asks to find the new angular velocity if an identical wheel is dropped onto the shaft. I got this part right.

Part b) is: Now suppose the dropped wheel starts with an angular velocity of 125 rpm is the opposite direction of the first wheel (CW from above). Determine the angular velocity for the resultant combination of the two wheels.

## Homework Equations

Conservation of angular momentum: L

_{i}=L

_{f}

L= Iω

## The Attempt at a Solution

Li=Lf

I(ω

_{CCW}) + Iω

_{CW}) = 2Iω

_{f}

I(26.180 rad/s) + I(-13.090 rads) = 2Iω

_{f}

13.09 = 2ω

_{f}

ω

_{f}= 6.545

Is that right? On my initial attempt (these are test corrections), I set the initial momentum of the first wheel equal to the sum of the final momentum and the initial momentum of wheel being dropped. My teacher wrote "same (stuck together)" on the paper, so I thought this might've been what he meant.