How Do I Solve This Rotational Motion Problem?

[coldblood]

Hi friends,
Please help me in solving this problem, I'll appreciate the help.

The problem is as:

https://fbcdn-sphotos-d-a.akamaihd.net/hphotos-ak-frc3/q71/s720x720/1470353_1461727604054345_1173881292_n.jpg

Attempt -

https://fbcdn-sphotos-e-a.akamaihd.net/hphotos-ak-prn2/q71/s720x720/1487447_1461727740720998_1698365428_n.jpg


Thank you all in advance.

 

[tiny-tim]

hi coldblood!

very good!

but your m is … ? ​

 

[coldblood]

hi coldblood!

very good!

but your m is … ? ​

Oh man, I think I would be solving this with unconscious mind. Sorry for that mistake and thanks a lot.