Weight = (mass) x (acceleration of gravity) .
Acceleration of gravity on a planet's surface is proportional to
(planet's mass) / (planet's radius)² .
On Earth's surface, acceleration of gravity is 9.8 m/s² .
Weight of 10 kg mass = (10 kg) x (9.8 m/s²) = 98 newtons.
On the surface of a planet with twice the Earth's mass
all stuffed into the same radius, the acceleration of gravity
would be 19.6 m/s² ... double what it is on Earth.
Weight of 10 kg would be (10 kg) x (19.6 m/s²) = 196 newtons ...
double its Earth weight.
