Download 1. The angular momentum of a system remains constant (a) when no

1. The angular momentum of a system remains constant
(a) when no net, external force acts on the system.
(b) when the total kinetic energy is constant.
(c) when no net, external torque acts on the system.
(d) when only conservative torques act on the system.
(e) all the time since it is a conserved quantity.
2. In the figure, the disk can rotate about an axis going through the middle of the disk.
The tangential velocity vector of the edge of the disk is shown. In what direction is
the angular momentum?
+y
vt
+x
3. What is the magnitude of the angular momentum of a 3.6 kg, 5.7-cm-diameter,
uniform disk rotating at 750 rpm about an axis going through the center of the disk?
4. How fast would a 175 g 45-cm-diameter hollow sphere have to rotate about its
symmetry axis to have an angular momentum of 2.5 kgm2 /s?
5. A 5.0-m radius playground merry-go-round with a moment of inertia of 2000 kgm2 is
rotating freely with an angular speed of 1.0 rad/s. Two people, each having a mass
of 60 kg, are standing right outside the edge of the merry-go-round and step on it
with negligible speed. What is the angular speed of the merry-go-round right after
the two people have stepped on?