Posted by sandhya on Monday, October 11, 2010 at 6:18am.
A 1kg mass hangs by a string from a disk with radius 5.1 cm which has a rotational inertia of 5 × 105 kg•m2. After it falls a distance of 1.4 meters, how fast is it going?
What is the angular velocity of the disk?

physics  drwls, Monday, October 11, 2010 at 7:53am
Is the string wound around the disc, so that the disc spins when the weight falls?
If so, then use
M g H = (1/2)M V^2 + (1/2) I*(V/R)^2
to solve for V, the velocity when H = 1.4 m.
The second term on the right is the disc's rotational kinetic energy. V/R is the angular velocity that they want. 
physics  sandhya, Monday, October 11, 2010 at 8:42am
Thanks a lot