- #1
archaic
- 688
- 214
- Homework Statement
- A uniform disk has a mass of 3.8 kg and a radius of 0.52 m. The disk is mounted on frictionless bearings and is used as a turntable. The turntable is initially rotating at 50 rpm. A thin-walled hollow cylinder has the same mass and radius as the disk. It is released from rest, just above the turntable, and on the same vertical axis. The hollow cylinder slips on the turntable for 0.20 s until it acquires the same final angular velocity as the turntable. What is the final angular momentum of the system?
- Relevant Equations
- ##L=I\omega##
There is no net external torque since the cylinder is slipping (no friction), so the angular momentum should be conserved.
$$L_f=\frac 12MR^2\omega_i=\frac 12\times3.8\times0.52^2\times50\times\frac{2\pi\times0.52}{60}$$
$$L_f=\frac 12MR^2\omega_i=\frac 12\times3.8\times0.52^2\times50\times\frac{2\pi\times0.52}{60}$$