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physicsflunky

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## Homework Statement

There is a record spinning when a blob of putty falls vertically on its edge; which is .10m from the center. What is the rotational speed of the record after the blob sticks on it?

additional information:

mass of blob = .040kg

mass of record = .10kg

rotational inertia of record before collision = .0005kg*m^2

rotational speed before collision = 4.5 rad/s

## Homework Equations

I = m(r^2)

Iwi = Iwf

I = Rotational Inertia

wi = Initial Rotational Velocity

wf = Final Rotational Velocity

r = distance from point of rotation to point of applied force

## The Attempt at a Solution

(calculate new rotational inertia)

I = m(r^2)

= .040(.10^2) = .0004

.0004 + .0005 = .0009

(set initial momentum equal to final momentum and solve for Wf)

4.5(.0005) = I(Wf)

.00225 = .0009(Wf)

2.5 = Wf

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