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

The pendulum consists of a uniform disk with radius r=10.0cm and mass 500g attached to a uniform rod with length L=500mm and mass 270g.

a. Calculate the rotational inertia of the pendulum about the pivot point.

(answer .205kg m^2)

b. What is the distance between the pivot point and the center of mass of the pendulum?

(answer 47.7 cm)

c. Calculate the period of oscillation.

(answer 1.5s)

2. Relevant equations

Ic for rod is 1/12 x M x L^2

Ic for disk is 1/2 x M x R^2

Io is Ic + mh^2, where h is from the point of pivot to the center of mas.

T=2 x pi x [Io / (mgh)]^(1/2)

3. The attempt at a solution

a. Ic = 1/12 x M x L^2 = (1/12) x (.270kg) x (.500m)^2 = .005625 kg m^2 the rod

Ic = 1/2 x M x R^2 = (1/2) x (.500kg) x (.100m)^2 = .0025 kg m^2 the disk

Io = Ic + mh^2, I don't know what to do with the two Ic, and cannot find the Io without h, which is to be found in question b. What am I missing?

b. Io = Ic + mh^2 = .205 kg m^2 = Ic + (.770kg)(h^2) to find h, but cannot find Ic with the two previous number I got. No Idea Need Help!

c. T= 2 x pi x [Io / (mgh)]^(1/2) =

2 x pi x [(.205kg m^2) / [(.770kg)(9.81m/s^2)(.477m)]]^(1/2)= 1.5s

can get with the answers for a and b

If someone had msn (horseland20@hotmail.com) I will be on if you can help if not post!

I would appreciate the help.

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# Homework Help: Calculate the rotational inertia of the pendulum

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