Question

The escape speed from a distant planet is 42 km/s. If the accelaration of gravity on the planet is 11.0 m/s/s, what is the radius of the planet?

Answer 1

The potential energy at the surface

GMp*m/radius but that is equal to 1/2 m vescape^2

Now you know "g", which is GMp/rad^2

or GMp=rad^2*11.0m/s

finally.
11.0* radius=1/2 vesc^2

check all that.