A solid disk with a mass of 0.8 kg and a radius of 12cm is rotating at a rate of 2.6 rev/s. Another disk with half the mass and half the radius is dropped on top of the first disk. What is the new angular speed of both disks when they are rotating together?

The new angular speed of both disks when they are rotating together is 2.311 revolutions per second.

Explanation:

This situation can be analyzed by the Principle of Conservation of Angular Momentum since there are no external forces and moments being exerted on the system, whose definition is presented below:

(1)

Where:

, - Initial and final angular speeds, measured in revolutions per second.

- Initial and final moments of inertia, measured in kilograms per square meter.

The initial and final moments of inertia of the system are, respectively:

(2)

(3)

By applying (2) and (3) in (1), we obtain the following expression:

(4)

If we know that , then the new angular speed of both disks when they are rotating together is:

The new angular speed of both disks when they are rotating together is 2.311 revolutions per second.

c) up

hope this

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.