A space station orbits the Earth with constant speed. What can be said about the space station's acceleration?
1.It is zero because the space station moves with constant speed.
2.It is greater than 9.8 m/s2 because the space station is moving so quickly.
3.It is less than 9.8 m/s2 because the space station is so high above the Earths surface.
4.It is equal to 9.8 m/s2.
Question 2
A planet has 3 moons, all of equal mass. Moon 1 is in a circular orbit of radius r. Moon 2 is in a circular orbit of radius 2r, and moon 3 is in a circular orbit of radius 3r. The ratios of the gravitational force exerted by the planet on each of the moons, 1, 2, and 3 are ________ respectively.
1.1:2:3
2.1:1:1
3.1:4:9
4.9:4:1