The two masses (m1 = 5.0 kg and m2 = 3.0 kg) in the Atwood's machine shown in Figure 10-23 are released from rest, with m1 at a height of 0.91 m above the floor. When m1 hits the ground its speed is 1.5 m/s. Assume that the pulley is a uniform disk with a radius of 12 cm.

Question

Determine the mass of the pulley.

Answer 1

Use a conservation of energy approach, and include the rotational kinetic energy of the pulley, KEr

KEr = (1/2)I w^2 = (1/4) m V^2

The radius of the pulley will cancel out. m is the mass of the pulley.

potential enegy change
= (1/2)[m1 + m2 + (m/2)] *V^2

I would need to see your figure 10-23 to know how the potential energy is related to the height.

Answer 2

3.43