What is the point of an object where the force of gravity is considered to act?

Gravity always acts downward on every object on earth. Gravity multiplied by the object's mass produces a force called weight. Although the force of an object's weight acts downward on every particle of the object, it is usually considered to act as a single force through its balance point, or center of gravity.

Oh i'm sorry. didn't see the options

Hello!

the answer is:

the correct option is the option b.

why?

to calculate the surface area of the right cylinder, we need to use the following formula:

from the picture we know that:

so, substituting and calculting we have:

hence, we have that the correct option is the option b.

have a nice day!