# Escape velocity problem

1. Problem
A rocket has landed on Planet X, which has half the radius of Earth. An astronaut onboard the rocket weighs twice as much on Planet X as on Earth. If the escape velocity for the rocket taking off from Earth is v , then its escape velocity on Planet X is

a) 2 v
b) (√2)v
c) v
d) v/2
e) v/4

I reasoned out this problem mathematically, but what is the conceptual reasoning behind this?

Related Introductory Physics Homework Help News on Phys.org
PeroK
Homework Helper
Gold Member
1. Problem
A rocket has landed on Planet X, which has half the radius of Earth. An astronaut onboard the rocket weighs twice as much on Planet X as on Earth. If the escape velocity for the rocket taking off from Earth is v , then its escape velocity on Planet X is

a) 2 v
b) (√2)v
c) v
d) v/2
e) v/4

I reasoned out this problem mathematically, but what is the conceptual reasoning behind this?
I would say this is a mathematical question. To see it more clearly, you could try to derive a formula for escape velocity in terms of the radius ##R## and the surface gravity ##g## of a planet.

• 15ongm
BvU
• 