Because a galaxy is a large collection of many stars, and almost every star radiates some visible light.
Answer:
It increases proportionally
Explanation:
The gravitational force between the Earth and an object on its surface is given by

where
G is the gravitational constant
M is the Earth's mass
m is the mass of the object
R is the Earth's radius
In this problem, the Earth's mass is increased, while the diameter (and therefore, the radius) doesn't change. From the equation, we see that the gravitational force is directly proportional to the Earth's mass: therefore, if the mass is increased, the force will increase as well by the same proportion (for example, if the mass is doubled, the force will double as well)
Answer: 7.5 rev/s
Explanation:
We are given the angular velocity
a helicopter's main rotor blades:

However, we are asked to express this
in the International Systrm (SI) units. In this sense, the SI unit for time is second (
):


Complete Question
The complete question is shown on the first uploaded image
Answer:
Explanation:
From he question we are told that
The first mass is 
The second mass is 
From the question we can see that at equilibrium the moment about the point where the string holding the bar (where
are hanged ) is attached is zero
Therefore we can say that

Making x the subject of the formula



Looking at the diagram we can see that the tension T on the string holding the bar where
are hanged is as a result of the masses (
)
Also at equilibrium the moment about the point where the string holding the bar (where (
) and
are hanged ) is attached is zero
So basically


Making
subject


Answer:
L = 2.8 cm
Explanation:
Period T = 4 / 12 = 1/3 s
T = 2π√(L/g)
L = (T/2π)²g
L = ((1/3)/2π)²9.8 = 0.02758... ≈ 2.8 cm