just search up the answer/ definition to all of them, rephrase into own words, then do the same for examples.
Answer:

Explanation:
The gravitational force between the proton and the electron is given by

where
G is the gravitational constant
is the proton mass
is the electron mass
r = 3 m is the distance between the proton and the electron
Substituting numbers into the equation,

The electrical force between the proton and the electron is given by

where
k is the Coulomb constant
is the elementary charge (charge of the proton and of the electron)
r = 3 m is the distance between the proton and the electron
Substituting numbers into the equation,

So, the ratio of the electrical force to the gravitational force is

So, we see that the electrical force is much larger than the gravitational force.
A variable is a letter so just be like
13a or something like that
Answer:
Gravitational force mg' =(49)mg=49×63=28N.
Explanation:
What is the gravitational force on it due to the Earth , at a height equal to half the radius of the Earth ? (Given that the radius of Earth = 6400 km). Gravitational force mg ( This is not the real explanation)
Answer:
300m per minute or 5m per second