Assignment:
A uniform, hollow, cylindrical spool has inside radius R/2, outside radius R and mass M as in the attached .jpg. It is mounted so that it rotates on a fixed horizontal axle. A counterweight of mass m is connected to the end of a string wound around the spool. The counterweight falls from rest at t = 0 to a position of y at time t. Show that the torque due to the friction forces between spool and axle is Tf= R { m [ g - (2y / t^2)] - M (5y / 4t^2)}
Provide complete and step by step solution for the question, use formulas.