I'm trying to figure out the answer to this question. It seems to easy, so I have my doubts.

Question

Question:
Calculate the minimum change in velocity (delta V or ∆V) required for the Orion MPCV to decrease its altitude to 60 miles if it’s orbiting with an apogee of 260 miles and a perigee of 220 miles above the surface of Earth

Use the rule of thumb that below an altitude of 500 miles, for every 2 feet per second (fps) change in the orbiting space craft’s velocity its altitude will change by 1 mile

I have the answer of -320/fps. by subtracting apogee (260) and perigee(220)
getting 160. Then multiplying -2X160 get my answer of -320/fps

Im not asking anyone to do the problem for me but guidance or example of a similar problem. thank you

Answer 1

160 milesalt decrease* 2fts/*milealt=your answer.

Answer 2

I'm not sure I understand your example. can you elaborate?

Answer 3

I repeated what you did...and you don't understand it?