A 70 kg student holds a 2.0 kg mass in each hand and is sitting on a stool that can

rotate freely about a vertical axis. With the masses held at arm’s length (0.9 m) the
student is set spinning at 1.2 revolutions per second.

a. If we approximate the student as a uniform density cylinder that is 1.3 m tall and
0.3 radius, then calculate their rotational inertia.

b. Calculate the contribution of the two masses to the overall rotational inertia.

c. If the student brings their arms in and holds the two masses at a radius of 0.1,
what is their new rotational speed?

2 answers

I wish i could help, i just know we both gon get rekt in phys140 together
L = Iω
You'll have to look up I for a solid cylinder and a mass at a distance. Also need to convert rev/sec into rad/sec.
When you have a) and b) add them for your total L. Find the new I for masses at the new distance. Then conservation of L