Solo estoy aquí por la libra, lo siento, no pude ayudar
Answer:
0.011 N-m
Explanation:
Given that
The mass of a solid cylinder, m = 30 kg
The radius of the cylinder, r = 0.18 m
The acceleration of the cylinder, 
It rotates about an axis through its center. We need to find the torque acting on the cylinder. The formula for the torque is given by :

Where
I is the moment of inertia of the cylinder,
For cylinder,

So,

So, the required torque on the cylinder is 0.011 N-m.
Answer:
B. In a vacuum, it is a constant value that does not depend on the observer.
Answer:
D. infinitely extended in all directions
Explanation:
A semi infinite solid is infinitely extended in every direction. It has a single surface and can extend when heat is applied.
The body of a semi infinite solid is idealised, that is, when there is heat present, it expands in all directions to infinity. It can be used for a thick wall because its shape can be changed when subjected to different levels of heat near its surface.
It is also expands as heat is applied because its thickness is negligible.
This idealized body is used for earth, thick wall, steel piece of any shaped quenched rapidly etc indetermining variation of temperature near its surface & other surface being too far to have any impact on the region in short period of time since heat doesn’t have sufficient time to penetrate deep into body thus thickness can be neglected