in terms of gravity what is the difference between g, G, and fg?

Question

is g the acceleration due to gravity?

Answer 1

g: a unit of acceleration, example g=9.8 m/s ^2 on earth

G: the universal gravitational constant, which is everywhere in the universe and has to be accounted for in Newtonian universal gravity as well as General Relativity. the most recent measurement of it is 6.693 x 10–11 cubic meters per kilogram second squared...which is random and meaningless to most people. you wont encouter it unless you're doing high level physics...

fg: force of gravity, which equals mass times the acceleration of gravity, fg = mg, so on earth the equation would look like this, fg = 100kg x 9.8 m/s^2

hope this helps!

edit: yes its acceleration due to gravity...

Answer 2

G is called the Newtonian Gravitational Constant. It is fixed for any point in the universe. Its value is very very small. We use G, to calculate the force between two bodies of mass m1 and m2. F = G*m1*m2 / r^2 whereas g, (small g),represents the acceleration of an object due to the earth's gravity. g=9.8 m/s^2 Now, g will vary as u go to moon, or a different planet. But G, will not change. Its a universal constant. Also, g varies for different heights. for example, if u go to a mountain on Earth, value of g will slightly change. Also, g=GM/R^2 where M is the mass of the earth and R is the radius of the earth. This formula, is used to calculate value of g, at the earth's surface. if u put mass of moon, and radius of moon in M and R resp. It will give u the acceleration due to gravity on moon.