(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A 500 gram piece of putty falls straight down and sticks to a 4 kg rotating solid disk below. The uniform disk has a radius of 3 meters, and the putty hits the disk 2.5 meters from its center. You may neglect all forces other than that of the collision.

a- If the disk was initially rotating at 10.0 rad/s, find its final angular velocity.

b- The putty takes 15 ms to collide with the disk. Calculate the avergae force on the putty.

2. Relevant equations

I = mr^2 and .5 mr^2, L = I omega

3. The attempt at a solution

For part a,

I found moment of inertia of the disk (I_d) = 1/2 * 4kg* (3m) ^2 =

18 kg m^2

moment of inertia of putty = .5kg*(2.5m)^2 = 3.13 kgm^2

Since the putty falls straight down, i assumed the initial angular momentum of the putty was 0. So the initial angular momentum of the system is L_d = 18kgm^2*10 rad/s) = 180 kgm^2/s

Lf = Li, so (I_p + I_d) * angular velocity = 180, angular velocity = 8.52 m/s.

I'm really unsure about this, so I just wanted someone to doublecheck it. Also, I dont really know how to find the average force for part b.

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# Homework Help: Conservation of Angular Momentum

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