Definition of gravitational force in Physics

On the surface of the earth the force of gravity is three times what it is on the surface of Mars.My muscles, perfectly attuned and accustomed to the force of gravity on Earth, played the mischief with me in attempting for the first time to cope with the lesser gravitation and lower air pressure on Mars.In long stretches they move at a sickening speed, especially on the upward trip, since the small force of gravity inherent to Mars results in very little opposition to the powerful force above.The bowman could not travel at the pace set by Carthoris, whose muscles carried him with great rapidity over the face of the small planet, the force of gravity of which exerts so much less retarding power than that of the Earth.It is said that the sap flows much more quickly on those days when the sun is powerful; and likewise, that it is absolutely necessary to take care, in cutting down the tree, that it should fall with its head upwards on the side of the hill; for if it falls down the slope, scarcely any sap will flow; although in that case one would have thought that the action would have been aided, instead of checked, by the force of gravity.The Weigh-Down helps eliminate "tarp ballooning", and best of all, no mechanical parts are required since it uses the natural and constant force of gravity.His biggest challenge is fighting the force of gravity.Then they sliced the model at nearly 30 million different combinations of angle and depth and calculated the capability of the rocks below the slices to resist the force of gravity and hold up the mass of rocks above.He called it a `maximum G-force maneuver, ' and it was basically (intended) to try to jolt it down by force of gravity, '' Spears said.Then try the Missile, which takes you 125 feet above the ground, looping the loop at two and a half times the force of gravity before doing it all again - backwardsThe airplanes are capable of handling forces ranging from plus or minus 10 G's - 10 times the force of gravity.Unlike radiation, the force of gravity cannot be shielded and is a unique new concept for the detection of shielded nuclear weapons.