What two factores combiend to keep earth in oribit around the sun and the moon in orbit around the earth?

Answer 1

Only one force is required: gravity ... the gravitational attraction between the

center of the earth and the center of the sun. If gravity were not at work, then

the Earth would take off in a straight line, into deep space. And if another force

were required, we'd be out of luck, since the gravitational attraction is the only

force that exists.

Answer 2

Gravity, and inertia. The inertia of any moving mass tends to keep it moving at a constant velocity, in a STRAIGHT LINE.

But if the Earth were moving in a straight line, it would move away from the Sun. The gravity of the Sun tries to pull the Earth down, and INTO the Sun. The delicate balance of inertial and gravity keep the Earth (and all the other planets) in stable orbits.

Answer 3

The Earth is kept in orbit around the Sun by the gravitational force between the

Earth and Sun. The Moon is kept in orbit around the Earth by the gravitational

force between the Moon and Earth.

In each case, the gravitational force is all that's needed, which is lucky, because

the gravitational force is all there is.

Answer 4

Inertia ("A body in motion will tend to remain in motion") keeps the Earth moving in a straight line out away from the Sun. Gravity, the attractive force between all mass in the universe, pulls the Earth directly toward the Sun.

Balanced together, the Earth is moving forward as it falls into the Sun. But the Earth is moving so fast - about 67,000 miles per hour in its orbit - that it keeps MISSING the Sun!

Answer 5

gravity pulls them together and motion in a circle keeps them apart , stable orbits are a precise balance of the two

Answer 6

Its mass and its velocity. All governing functions of Earth's position rely on these two factors.

Answer 7

The Sun's gravity and the Earth's velocity (at a tangent to its orbit, at any instant) around the Sun.

Answer 8

Gravity and momentum. Gravity causes the moon to continually "fall" toward Earth, and momentum causes it to always miss, because the momentum stays perpendicular to the force of gravity.

Answer 9

Gravity is the only thing required to keep objects in orbit,

which is pretty lucky, because that's all there is.

Answer 10

The two factors are gravity and inertia.