# Natural vibration - energy method

1. May 6, 2010

### luznyr

1. The problem statement, all variables and given/known data

the problem is in the attached file, im having trouble with part d and e. cheers. [the answer for B is mr^2(0.5-16/9pi^2)]

2. Relevant equations

3. The attempt at a solution

i wont upload all my working as i have stuff everywhere but for part d:

i got my answer as 0.5I*(omega^2) + 0.5*m*(r*theta^2+(4r/3pi)^2), using the formula for total kinetic energy as 0.5Iomega^2+0.5mv^2

and part e: mgR(theta.sintheta + costheta - 1)

are these along the right tracks?
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

#### Attached Files:

• ###### Screen shot 2010-05-06 at 10.15.12 PM.png
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2. May 12, 2010

### timyew

are you sure your question 3 is correct?

3. May 12, 2010

### luznyr

im not too sure what you mean question three sorry, if by part C, then i'm not too concerned about that for the moment, just part D and E

4. May 12, 2010

### timyew

sorry... i mean D

5. May 12, 2010

### luznyr

i have no idea if either of my answers for d or e are right, hence why i stuck it on here....im just so confused haha

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