(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A spaceship of mass m circles a planet (mass = M) in an orbit of radius R. How much energy is required to transfer the spaceship to a circular orbit of radius 3R?

2. Relevant equations

K=.5mv[tex]^{2}[/tex]

U[tex]_{g}[/tex]=-[tex]\frac{GMm}{r}[/tex]

v=2(pi)r/T

v=(ar)^.5

3. The attempt at a solution

I had no idea how to do this problem. I thought about subtracting the total final energy from the total initial energy to get the energy input required, but I didn't know how to find v. The two equations I could think of for find v are listed above

It would be nice if you guys could at least give me a hint as to how to solve this test problem, since I get to have a second try at it tomorrow.

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Energy required to transfer an object to a higher orbit

**Physics Forums | Science Articles, Homework Help, Discussion**