Energy needed for pluto to escape earth surface

[jperk980]

Calculate the amount of energy required to escape from the surface of the following bodies, relative to that required to escape from the surface of Earth.(a) Pluto

I keep on getting the same answer to be .011092137 but according to the website i am working on that is not correct. I used the mass of Earth to be 5.98e24, mass of Pluto is .002*5.98e24 and the radius's of Earth is 6.378e6 and Pluto is 1.15e6. I understand that (Mp*Re)/(Me*Rp) should be the correct formula.

If you get a different answer please help me achieve the answer you got because i have been trying many different solutions and still have not been able to figure out the question. I have a 5% grace period which all answers within 5% are correct.
Thank you

 

[Doc Al]

Your formula looks correct.

 

[belliott4488]

I understand that (Mp*Re)/(Me*Rp) should be the correct formula.

This is the correct formula for what? Ratio of velocities? I don't think so.

Where did you get this expression, and can you derive it? You should be able to, if you want to understand the problem completely. Try doing that, and I think you'll see what you need to do to correct the expression that you gave above. If you're not sure how to do that, just ask.

 

[belliott4488]

Your formula looks correct.

oops. We crossed responses.

Are you sure he's correct? For ratio of escape velocities? KE is proportional to v^2 and PE is proportional to M/R, right? Unless I missed a radical sign somewhere, that's not what I get ...

 

[Doc Al]

The question asked for energy, not velocity:

Calculate the amount of energy required...

 

[Bright]

In original post the question is about energy, not velocity

Calculate the amount of energy required to escape from the surface of the following bodies, relative to that required to escape from the surface of Earth.(a) Pluto

 

[belliott4488]

aughh! SORRY! I mis-read it, as you've noticed ... and I keep crossing messages.

Never mind me!

(except that I now agree with jperk's original answer)