Sketch a free-body diagram for the hanging mass m.
The mass accelerates down when the system is released from rest. Apply Newton's Second Law to find the relationship between T, the tension, and a, the acceleration.
What is the connection between a, the angular acceleration of the disk, and a?
Show how combining your two equations above with equations (1) and (2) in the lab manual will give you equation (3) in the manual.
The tension is not the only force producing a torque. There is also a frictional torque present that opposes the disk's motion (this is minimized by supporting the disk on a cushion of air). Use the "Top View" of the experiment in the simulation to answer the following questions.
When the mass is falling, and the disk is speeding up, how does the direction of the frictional torque compare to the direction of the torque from the string?
Same Direction | Opposite Direction |
Same Direction | Opposite Direction |
Speeding up | Slowing down | Equal in both cases |