Answer:
B) Friction
Explanation:
Friction is a force that acts when an object is sliding along a surface. Microscopically, this force is due to the fact that the two surfaces are not perfectly smooth, but they have "imperfections" that cause a force that opposes the motion of the object.
For an object sliding on a flat surface, the force of friction has magnitude:

where
is the coefficient of kinetic friction
m is the mass of the object
g is the acceleration of gravity
The direction of the force of friction is always opposite to the direction of motion of the object.
In reality, friction also acts if the object is at rest and it is pushed by a force; in this case, we talk about static friction, and its magnitude is

where
is called coefficient of static friction, and it is generally larger than the coefficient of kinetic friction.
Answer:
B-Large groups of stars held together by gravity
Explanation:
Answer:

Explanation:
The intensity is related to the power and surface area by
. We need to calculate the surface area of a sphere of radius r=4.3ly.
Since 4.3ly is the distance light travels in 4.3 years at 299792458m/s, we can obtain it in meters by doing:

So we have:

Answer: Solubility
Solubility is the ability to be dissolved. Saturation is when the concentration is too high(more than solubility) that when you add another material it won't dissolve. Solute is the material that dissolved. Solvent is the material that used for dissolving
The Green work gymno means Naked