Universal Gravitation problem, help with final statement.

[Physics345]

Homework Statement

earth has a mass of 5.98x10^24 kg and the moon has a mass of 7.35x10^22 kg. The distance from the centre of the moon to the centre of the Earth is 3.84x10^8 m. A rocket with a total mass of 1200 kg is 3.0x10^8 m from the centre of the Earth and directly in between Earth and the moon. Find the net gravitational force on the rocket from the Earth and moon.

Homework Equations

Fnet=Gm1m2/r^2 + Fnet=Gm2m3/r^2

The Attempt at a Solution

Rocket to earth:
Fnet=5.32N=5.3N
Rocket to the moon:
Fnet=5.32N-0.833
Fnet=4.48N=4.5N rounded
Therefore, the net force of the rocket to the moon is 4.5N Right and the net force from the rocket to Earth is 5.3N Left.

I was just wondering if my Final statement is correct.

 

[haruspex]

Fnet=Gm1m2/r^2 + Fnet=Gm2m3/r^2

the net force of the rocket to the moon

You do not seem to understand "net force". It is the sum of all the applied forces, so there is only one net force on the object.

4.5N Right

Left/right depends on your diagram. Better to write in terms of "towards moon" or "towards Earth".

 

[Physics345]

Fnet means the total/sum of all forces. That was a typo I meant to put FgE= Gm1m2/f13 FgM=Gm2m3/f23 Fnet=FgE-FgM fatigue is very intoxicating but thanks I figured out the answer to my question anyways. The answer is 4.5N Right towards the Moon and 4.5 Left towards Earth.

 

[haruspex]

Fnet means the total/sum of all forces. That was a typo I meant to put FgE= Gm1m2/f13 FgM=Gm2m3/f23

Ok, but my comment still applies to your answer. You are asked for the net force; that's just one force, not a separate force towards each attractor.

 

[Physics345]

Sorry I edited my comment, I'm just really tired I edited as you replied, so I can see how you came to that conclusion.

 

[haruspex]

4.5N Right towards the Moon and 4.5 Left towards Earth.

Better, but as I wrote, left and right refer to some diagram (that I cannot see). Just write that it is 4.5N towards ... which one?

 

[Physics345]

Oh Ill upload it now

 

[haruspex]

Oh Ill upload it now

No, I don't need the diagram. The point is that you should not be referencing a diagram in your answer.

 

[Physics345]

No, I don't need the diagram. The point is that you should not be referencing a diagram in your answer.

Oh, I should be stating 4.5N Towards the Earth and 4.5N Towards the moon. Wow I feel silly, left and right shouldn't even be stated in this scenario.

 

[Physics345]

Statement revised, here is my new final statement. Therefore, the net force of the rocket towards the Moon is 4.5N, and 4.5N towards the Earth.

 

[haruspex]

Statement revised, here is my new final statement. Therefore, the net force of the rocket towards the Moon is 4.5N, and 4.5N towards the Earth.

There is a single net force on the rocket. You can specify it as a magnitude and direction. Magnitudes are non-negative by definition. Direction is either towards the moon or towards the Earth. Which?

 

[Physics345]

There is a single net force on the rocket. You can specify it as a magnitude and direction. Magnitudes are non-negative by definition. Direction is either towards the moon or towards the Earth. Which?

Towards the Earth because the Earths gravitational pull is pulling the rocket!

 

[haruspex]

Towards the Earth because the Earths gravitational pull is pulling the rocket!

They are both pulling the rocket. Which wins?

 

[Physics345]

They are both pulling the rocket. Which wins?

I would have to say the Earth wins, considering that the gravitational pull of the Earth is about 83% greater than the moons even after taking the altitude of the rocket into account.

 

[Physics345]

Wow it says it in my answer, the pull of the Earth on the rocket is 5.3N as opposed to the moon, which has a measly 0.8338N.

 

[haruspex]

Wow it says it in my answer, the pull of the Earth on the rocket is 5.3N as opposed to the moon, which has a measly 0.8338N.

Right!
So why did you write this:

4.5N Right towards the Moon and 4.5 Left towards Earth

and this:

the net force of the rocket towards the Moon is 4.5N, and 4.5N towards the Earth.

(which would add to zero net force) and this:

because the Earths gravitational pull is pulling the rocket!

?

 

[Physics345]

The answer was in my face this whole time I feel very dumb. Considering the lack of sleep I've had lately it's reasonable, well I probably should head to bed and catch up on some needed sleep. I'm sure this was frustrating for you, I can just imagine... I was able to do the math perfectly but I couldn't get the wording out for the final statement. Thanks a lot though I really appreciate it. Note,I wrote all that because I'm honestly being brain dead right now. I can write out all the math flawlessly my issue is wording when it comes to science I over think things and over complicate science a lot. But with more studying and practice I should have all this down to the point you'll see me on here helping people out =). If you want I could type out all the math I wrote but I decided to type out as little as possible because I was tired, but now that I want to prove a point here's the math:
FgE= Gm1m2/F13 FgM=Gm2m3/F23
Fnet=FgE - FgM
F13(distance Earth to rocket)=3.0 x 10^8
F23(distance rocket to earth)=(3.84 x 10^8) - (3.0 x 10^8)= 8.4 x 10^7
Fnet=(6.67 x 10^-11)(5.98 x 10^24)(1.2 x 10^3)/(3.0 x 10^8)^2 - (6.67 x 10^-11)(1.2 x 10^3)(7.35 x 10^22)/(8.4 x 10^7)^2
Fnet=5.32N - 0.8338N
Fnet=4.5N

 

[haruspex]

The answer was in my face this whole time I feel very dumb. Considering the lack of sleep I've had lately it's reasonable, well I probably should head to bed and catch up on some needed sleep. I'm sure this was frustrating for you, I can just imagine... I was able to do the math perfectly but I couldn't get the wording out for the final statement. Thanks a lot thought I really appreciate it. Note,I wrote all that because I'm honestly being brain dead right now. I can write out all the math flawlessly my issue is wording when it comes to science I over think things and over complicate science a lot. But with more studying and practice I should have all this down to the point you'll see me on here helping people out =). If you want I could type out all the math I wrote but I decided to type out as little as possible because I was tired, but now that I want to prove a point here's the math:
FgE= Gm1m2/F13 FgM=Gm2m3/F23
Fnet=FgE - FgM
F13(distance Earth to rocket)=3.0 x 10^8
F23(distance rocket to earth)=(3.84 x 10^8) - (3.0 x 10^8)= 8.4 x 10^7
Fnet=(6.67 x 10^-11)(5.98 x 10^24)(1.2 x 10^3)/(3.0 x 10^8)^2 - (6.67 x 10^-11)(1.2 x 10^3)(7.35 x 10^22)/(8.4 x 10^7)^2
Fnet=5.32N - 0.8338N
Fnet=4.5N

OK!
Get some rest...

 

[Physics345]

HaHa, thanks again. Good night!