Plz help me it is improtant

Aregion of space in which a measurable gravitational force is indicated by the force exerted on a test mass is called

1.what is where an object is located 2. what is how fast an objects speed is changing 3. what is how fast an object is moving

Identify the correct relation showing that the radius r of the orbit of a moon of a given planet can be determined from the radius r of the planet, the acceleration of gravity at the surface of the planet, and the time τ required by the moon to complete one full revolution about the planet. determine the acceleration of gravity at the surface of the planet jupiter knowing that r = 71 492 km and that t= 3.551 days and r= 670.9 × 10^3 km for its moon europa.