Gravitional force of attraction & field- what's the difference? (1 Viewer)

[VuongstER_boi]

Hi ppls,

I was wondering what is the difference in signficance between the formula:

1.F= Gm1m2/r^2(graviitational force of attraction)
& the formula: 2.g= Gm/r^2. ( gravitational field)

Like, I read the textbook and I still dont get the difference between the signficance of those two formulas.

What's the difference between these two formulas , hence the difference between the concepts?

 

[Kirjava]

Well, it applies to attractions between any object and the earth -- the mass need not be near the surface. Love nitpicking. (Referring to GM/r^2, of course F=mg has the value 'g' determined for the radius of the earth) <- Edit

The formula GM/r^2 refers to the gravitational field (a vector field), which has a certain value and direction for every point in space around the object M. To find the force on an object A, we multiply the field strength at A by A's mass (m), which is essentially the "multiplier" for the force. That is, a unit mass will experience a force numerically equal to GM/r^2 (although "1kg" should technically be included to get the units for force-- newtons), a 2kg mass 2GM/r^2 a 500gram mass 0.5GM/r^2 etc etc.

Hope thats helpful vuong.

 

[A High Way Man]

field is where the force acts.

 

[ownagemaster]

1.F= Gm1m2/r^2(graviitational force of attraction)
This gives the force of attraction due to gravity on two bodies.

2.formula: 2.g= Gm/r^2. ( gravitational field)
Gives the strength of the gravitational field for a specific body.

Gravitational force is the force experienced by a mass in a gravitational field.

A gravitational field is a region in space in which a mass experiences a force.

Hope this helps.

 

[Forbidden.]

1.F= Gm1m2/r^2(graviitational force of attraction)
This gives the force of attraction due to gravity on two bodies.

2.formula: 2.g= Gm/r^2. ( gravitational field)
Gives the strength of the gravitational field for a specific body.

Gravitational force is the force experienced by a mass in a gravitational field.

A gravitational field is a field in which a mass experiences a force.

Hope this helps.

1.
Between two bodies.
We assume a closed system
(like the two bodies are enclosed in an invisible cube or rectangular prism with no interference from the outside world or universe)
An analogy would be pretend the bodies 1 and 2 are complete loners and are the only two things with mass that exist in the universe and therefore the only gravity that exists is between them two.

 

[ownagemaster]

You could probably deduct that from the equation considering it only specifies two bodies

 

[Arowana21]

so yeh....they pretty much said it
1= between 2 bodies (i e 2 different planets)

2= gravitation force of ONE body, ie sub in Earth's mass and radius and u should get g=9.8

 

[Captain Gh3y]

A field is a region of space where a particular type of object will experience a force

The field strength is in force per unit -something-,

e.g. an electric field is a region where a charged particle will experience a force, and electric field strength is in force per unit charge

A gravitational field is a region where a particle that has mass will experience a force, and gravitational field strength is in force per unit mass.

Well F = ma, so force per mass is the same thing as acceleration. The formula was

g= Gm₁/r^2

That is the force per unit mass (i.e. acceleration) experienced by a massive object placed in the gravitational field of m₁. Most commonly that m will be the mass of earth, since you'll usually see problems about gravity on earth.

If you multiply force per unit mass by the mass of the particle in the field, you get the force experienced: (that statement should be really obvious)

So the formula looks like

F= Gm₁m₂/r^2

And you can see it's just the first formula multiplied by the mass of the object placed in the gravitational field.

The two masses are actually interchangeable; if you put your mass in the Gravitational Field formula you can work out what acceleration the earth will experience due to you.

 

[Ringa]

Newton's Third Law is wrong: Although it states that for each action, there is an equal and opposite reaction, there is no force equal in reaction to a Chuck Norris roundhouse kick.