Solving Wheel & Mass Problem - Brandon Seeking Help

[trojsi]

Hi folks,
In a tutorial I was given this problem on which I've been trying to solve these last 2 day with non luck. The Problem is attached with a diagram. I tried to take the torque as being T=mg-mR$$\alpha^{2}$$ but it was all in vein. Any help would be much appreciated

Thanks

Brandon

 

[SteamKing]

Clearly, mg is a force. What else do you need to convert this term into a torque?

 

[trojsi]

the thing is that I need to derive an equation to the one given and explain the steps involved, I will try to upload a more clear copy of the question.

 

[trojsi]

Yeah, youre right, I was mistaken, torque is not a force, sry. Any Clues please?