Could be c because it matches the question
The Coulomb's force acting between two charges is

where

is the Coulomb's constant, q1 and q2 the two charges, and r the distance between them.
Using

, we can find the distance between the two charges when the force is F=19.2 N:
Answer: 2561.7 pounds
Explanation:
If we assume the total weight of an airplane (in pounds units) as a <u>linear function</u> of the amount of fuel in its tank (in gallons) and we make a Weight vs amount of fuel graph, which resulting slope is 5.7, we can use the slope equation of the line:
(1)
Where:
is the slope of the line
is the airplane weight with 51 gallons of fuel in its tank (assuming we chose the Y axis for the airplane weight in the graph)
is the fuel in airplane's tank for a total weigth of 2390.7 pounds (assuming we chose the X axis for the a,ount of fuel in the tank in the graph)
This means we already have one point of the graph, which coordinate is:

Rewritting (1):
(2)
As Y is a function of X:
(3)
Substituting the known values:
(4)
(5)
(6)
Now, evaluating this function when X=81 (talking about the 81 gallons of fuel in the tank):
(7)
(8) This means the weight of the plane when it has 81 gallons of fuel in its tank is 2561.7 pounds.
Answer:
1. Main Sequence - middle life 17
2. red
3. blue
4. White dwarf stars are much hotter than Red Supergiants 15. List the color of the stars from hottest to coldest: Blue, White, Yellow, Orange, Red 16.
5. red giants
Explanation:
Main sequence stars have a Morgan-Keenan luminosity class labeled V. red giant and supergiant stars (luminosity classes I through III) occupy the region above the main sequence. They have low surface temperatures and high luminosities which, according to the Stefan-Boltzmann law, means they also have large radii. White dwarf stars are much hotter than Red Supergiants 15. List the color of the stars from hottest to coldest: Blue, White, Yellow, Orange, Red 16. The hottest stars are the blue stars. A star appears blue once its surface temperature gets above 10,000 Kelvin, or so, a star will appear blue to our eyes. The lowest temperature stars are red while the hottest stars are blue. Astronomers are able to measure the temperatures of the surfaces of stars by comparing their spectra to the spectrum of a black body. Most stars, including the sun, are "main sequence stars," fueled by nuclear fusion converting hydrogen into helium. ...
As stars begin to die, they become giants and supergiants (above the main sequence).