The force of gravity experienced by an object on a planet can be calculated using the following formula:
Fg = G*M/r^2
Here, Fg is the force of gravity experienced by the object, G is the gravitational constant (6.67 x 10^-11 N m^2 / kg^2), M is the mass of the planet, r is the distance between the center of the planet and the object.
Let's substitute the values into the formula:
Fg = (6.67 x 10^-11 N m^2 / kg^2) * (6 x 10^23 kg) / (3 x 10^6 m)^2
Fg = (6.67 x 10^-11 N m^2 / kg^2) * (6 x 10^23 kg) / (9 x 10^12 m^2)
Fg = (1.334 x 10^-7) N = 0.1334 N
Hence, the force of gravity on a 75-kg astronaut standing on this planet would be 0.1334 N, which is approximately 1/50 of the force of gravity on Earth.