Planets A and B have the same size, but planet A is half the mass of planet B. Which statement correctly explains the weight you would experience on each planet? Newton's law of gravitation is g r a v i t y = 1 2 2 F gravity ​ = r 2 Gm 1 ​ m 2 ​ ​ . The gravitational constant G is 6.67 × 10–11 N·m2/C2. (For the purposes of calculating the gravitational force between a planet and an object on its surface, the distance r is the radius of the planet.) Planetary body Mass, kg Radius, m Earth 5.97 × 1024 6.37 × 106 Moon 7.35 × 1022 1.74 × 106 Mars 6.42 × 1023 3.39 × 106 Mercury 3.30 × 1023 2.44 × 106.