Spherical planet A has mass m and radius r. Spherical planet B has mass and  radius 2r. How does the gravitational field strength at the surface of planet B compare to the gravitational field

strength at the surface of planet A?

a) It is the same as planet A

b) It is twice that of planet A

c) It is half that of planet A

d) It is one-eighth that of planet A

2 answers

Spherical planet B has mass (?????) and  radius 2r.
the mass is m/2, or b.

what will be the answer?