Apotter's wheel (a solid, uniform disk) of mass 7.0 kg and .65 m radius spins about its central axis. a 2.1 kg lump of clay is dropped onto the wheel at a distance .41 m from the axis. calculate the rotational inertia of the system.

a. 2.5 kg · m2
b. 1.8 kg · m2
c. 1.5 kg · m2
d. 0.40 kg · m2

The rotational inertia of the system is 1.8 kg.m².

(b) is correct option.

Explanation:

Given that,

Mass of disk = 7.0 kg

Radius = 0.65 m

Mass of clay = 2.1 kg

Distance = 0.41 m

We need to calculate the rotational inertia of the system

Using formula of rotational inertia

Where, I= the moment of inertia of a solid disk

I'=the moment of inertia of lump of clay

Put the value into the formula

Hence, The rotational inertia of the system is 1.8 kg.m².

there are no correct statementd on the list of choices you provided.

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.