Question

F=G(m1 x m2)/r²
anyone know how to use this equation?

Answer 1

\[F= G\frac{m_1m_2}{r^2}\]
Is Newton's Law of Universal Gravitation.
F being the Force
G is the gravitational constant
m_1 and m_2 are the two masses of the bodies
and r is the distance between them (from the center of each mass)

\[G\approx6.67384 \times10^{-11}N\frac{m^2}{kg^2}\]

Answer 2

How does it explain why earth won't being suck into center of the sun? and why? earth's orbit is oval instead of circle?

Answer 3

This equation alone does not suggest that the earth will not be sucked into the sun. If the earth was stationary the force of gravitation would act unilaterally to draw the earth toward the sun. Since gravity has no positive or negative charge, all stationary particles in the universe tend to be drawn together (e.g. nebulae).

The reason that the earth is not sucked into the sun is due to it's velocity, which is at a right angle to the force of gravity, like a ball being swung around on a string. Why doesn't the ball get sucked toward your hand if the force of the string is acting in that direction?
Because of the tangential velocity of the ball as it swings.

Here is a basic diagram of the situation with a planet and the sun: From the picture you can see that gravity is acting to change the velocity of the planet and direct it towards the sun. Because the planet is moving tangentially at a sufficient speed, it falls toward the sun but "misses" impact. If V=0 or is small enough, its tangential motion will not be enough to miss the sun, and the planet would collide with it.