Natural vibration - energy method

[luznyr]

Homework Statement

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

Homework Equations

The Attempt at a Solution

i won't 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?

 

[timyew]

are you sure your question 3 is correct?

 

[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

 

[timyew]

sorry... i mean D

 

[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