Jupiter has about 300 times the mass of Earth and about ten times Earth's radius. What's the Estimated size of g on the surface of Jupiter?

Since gravitational forces between two masses are proportional to m1 & m2, a 300x increase in planetary mass would INCREASE the gravitational force on an object by the same factor: 300x compared to earth. Since gravitational forces are also proportional to 1/(radius squared), a 10x increase in planetary radius would DECREASE the gravitational force by a factor of 100x (10 squared), at the planet's surface. So an object on such a planet would experience gravitational forces 3x greater than those on earth.

Since gravitational forces between two masses are proportional to m1 & m2, a 300x increase in planetary mass would INCREASE the gravitational force on an object by the same factor: 300x compared to earth. Since gravitational forces are also proportional to 1/(radius squared), a 10x increase in planetary radius would DECREASE the gravitational force by a factor of 100x (10 squared), at the planet's surface. So an object on such a planet would experience gravitational forces 3x greater than those on earth.