Gravitational Field Question

[EE123]

Homework Statement

A 12 kg meteor experiences an acceleration of 7.2 m/s^2, when falling towards the earth.

a.) How high above the Earth's surface is the meteor?

b.) What force will a 30 kg meteor experience at the same altitude?

Homework Equations

Fg = ma , Fg =Gm1m2 / r^2

The Attempt at a Solution

a = Fg / m, thus:

Fg / m = Gm1m2 / r^2

then:

r = √ (Fg / Gm1m2(m))

I got this far, somewhat understanding what I was doing the equation manupulation. Please help me! I searched this question up, but that thread was not helpful.

I don't know how to solve the question. The altitude is the radius from the earth? and since a = Fg / m, :S I equated this with the Fg = Gm1m2 / r^2, :|.

Please help!

 

[HallsofIvy]

Homework Statement

A 12 kg meteor experiences an acceleration of 7.2 m/s^2, when falling towards the earth.

a.) How high above the Earth's surface is the meteor?

b.) What force will a 30 kg meteor experience at the same altitude?

Homework Equations

Fg = ma , Fg =Gm1m2 / r^2

The Attempt at a Solution

a = Fg / m, thus:

Fg / m = Gm1m2 / r^2

then:

r = √ (Fg / Gm1m2(m))

I got this far, somewhat understanding what I was doing the equation manupulation. Please help me! I searched this question up, but that thread was not helpful.

Do you understand what "Gm1m2/r^2" means? What is G? What are m1 and m2?
A really major error is setting "a= Fg/m= Gm1m2/r^2". "Gm1m2/r^2" is the force due to gravity, not the acceleration. What you want is Fg= ma= Gm1m2/r^2.

Now, again, what are m1 and m2?

I don't know how to solve the question. The altitude is the radius from the earth? and since a = Fg / m, :S I equated this with the Fg = Gm1m2 / r^2, :|.

That wolyld be correct but you didn't! You equated it to a, not Fg.

Please help!

 

[EE123]

Do you understand what "Gm1m2/r^2" means? What is G? What are m1 and m2?
A really major error is setting "a= Fg/m= Gm1m2/r^2". "Gm1m2/r^2" is the force due to gravity, not the acceleration. What you want is Fg= ma= Gm1m2/r^2.

Now, again, what are m1 and m2?


That wolyld be correct but you didn't! You equated it to a, not Fg.

Yes I do understand what the equation: Fg = Gm1m2 / r^2 this is what my notes say (taking an online physics course, they provide notes)

G = gravitational field constant, m1 and m2 are the two masses, Fg = the force of gravity acting on each object,

r = the distance between the centres of the two masses.

this is the Newtons law of universal gravitation in the above equation form.

So ma = Gm1m2 / r^2 ??

which means r = √ (ma / Gm1m2)?

m1 would be the Earth's mass and m2 would be the meteor mass? but the mass, m2, would cancel out right?

 

[SammyS]

Yes I do understand what the equation: Fg = Gm1m2 / r^2 this is what my notes say (taking an online physics course, they provide notes)

G = gravitational field constant, m1 and m2 are the two masses, Fg = the force of gravity acting on each object,

r = the distance between the centres of the two masses.

this is the Newtons law of universal gravitation in the above equation form.

So ma = Gm1m2 / r^2 ??

which means r = √ (ma / Gm1m2)?

m1 would be the Earth's mass and m2 would be the meteor mass? but the mass, m2, would cancel out right?

It looks as if you have three different masses, m₁, m₂ and m. There are only two objects, so there should only be two different masses.

 

[Villyer]

ma = Gm1m2 / r^2 ??

which means r = √ (ma / Gm1m2)?

m1 would be the Earth's mass and m2 would be the meteor mass? but the mass, m2, would cancel out right?

The top equation is right, but you solved for r wrong.
And you are right about m2, it does cancel.