A collapsible uniform sphere has a mass of 1.5kg and a radius of 20cm. This sphere is originally spinning with a rotational velocity of 18rad/s. The sphere is then shrunk so that it has a radius of 15cm in a process that reduces its size but doesn’t produce a torque on the sphere, nor does it change its mass. What is the rotational velocity of the sphere after it shrinks?

A 153 g baseball is pitched at 27.89 m/s and spinning at 40 rad/s. You can treat the baseball as a uniform solid sphere of radius 4 cm. What fraction (in %) of its kinetic energy is rotational?

A 70 kg disk is spinning about a vertical axis of rotation with a radius of 1.2 m and a rotational inertia of 0.45 mr2 and it has an initial angular velocity of 10 rad/s. An unknown mass falls onto the disk 0.8 m away from the axis of rotation. After the collision, the disk is now spinning at 6 rad/s. The rotational inertia of the mass is mr2. Calculate the unknown mass that falls on the disk.

Can you help me with this physics problem please? On a xy plane, there are three masses are attached rigidly to a ligt board. There is a 5 kg mass at (-4m, 5m), a 2 kg mass at (0,-2m) and a 3kg mass at (3m,0). It is rotating around the x axis at 1.75 rad/s. What is the rotational kinetic energy?