The escape velocity from planet A is double that for planet B. The two planets have the same mass.

What is the ratio of their radii r A / r B?

r A / r B =_________

### 2 Answers

Ve = sqrt (2GM/r)

Ve.a = 2Ve.b

Ve.a/Ve.b = 2 = sqrt (r.b/ra)

r.a/r.b = 1/2^2 = 1/4

Here is your equation:

escape velocity = sq root(GM/r)

G and M are both constants here. Can you figure out the ratio from this?