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5 answers

It is called 'universal' because it works for any mass, microscopic or astronomic.

2006-11-23 09:04:10 · answer #1 · answered by Steve 7 · 0 1

It's called "Universal" because it applies everywhere and to everything. It's significance is that it is a measure of the strength of the gravitational force. The larger the gravitational constant, the stronger the gravitational force. The other factors in Newton's equation tells you what else influences how strong the gravitational force an object will feel, i.e. how far apart are the objects, and how massive are the object.

F = GMm/r^2, G = 6.6742 x 10^-11 (N m^2 / kg^2)

Similarly, Coulomb's Law is the equivalent equation for the electric force:

F = KQq/r^2, K is the electrostatic constant and

K = 8.988 × 10^9 (N m2 / C^2)

As you can see that electrostatic or electromagnetic force is significantly stronger than gravity, by a factor of 10^20!!!

2006-11-23 09:11:09 · answer #2 · answered by PhysicsDude 7 · 1 0

PhysicsDude has an excellent explanation, and I present mine here. The person posted directly above me has totally misunderstood the question: you're fired.

The Universal Gravitation Constant is "universal" because it literally applies anywhere in the universe. It is significant because it represents a ratio between the gravitational force between two objects and their masses, and distance from their centres. If the ratio were higher, it would represent an increase in the magnitude of gravitational attraction between objects, lower would represent a decrease.

That is, obviously, gravitational force is directly related to mass and inversely related to radius, through (m1)(m2)/r^2. (Note that it is NOT in the 'direction of -r' as r is a scalar quantity and has no direction; the bodies move towards each other - there is no negative gravitational force unless something has negative mass). So obviously the force is equal to these variables somehow.

However, using the value of newtons (kg-m/s^2), the values produced by the direct equation of (m1)(m2)/r^2 were much too high. Through practical experiments, empirical evidence led to the realization that all forces were related to the previously state equation by the constant 6.6742 x 10^11 Nm^2/kg^2

Noting that N = kg-m/s^2, technically the unit for the constant could also be (kg)(m) m^2/ s^2 (kg^2) = m^3/(kg-s^2)

2006-11-23 10:27:42 · answer #3 · answered by Anonymous · 1 1

You mean G? The formula for the attraction between two objects is F = G(mM/r^2) in the direction of -r. G is constant throughout the Universe, and is a property of the force. It does not depend on the objects or the distance between them.

EDIT: The second r is a unit vector pointing away from M, gravitation attracts m towards M, so the force points down negative r.

2006-11-23 09:06:59 · answer #4 · answered by Edgar Greenberg 5 · 0 0

Everything in the universe has gravity, so gravity is universal.

2006-11-23 09:32:48 · answer #5 · answered by spir_i_tual 6 · 0 1

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