Question

A uniform disk (I =

Answer 1

T - mg = ma
Since we know what mg is, we have to find a in terms of T, and solve for T
We know that the Torque about the pulley is Torque = r x F, and since Mg passes through the pulley's center, we don't have to consider it. We only consider T.
2) Torque = r x F = TR
Now, remember that Torque = I(alpha), and alpha = a/R?
TR = I(alpha) [Let's do some substitution]
TR = MR^2/2 * a/R
So, a = 2T/M.
Now let's solve for T!
Go back to 1) and rearrange it. T + ma = mg. Now plug in a.
So, we have that T = mg/(1+2m/M). T = 23.52N which is 24.