Ashwin
Last Activity: 10 Years ago
It is important to note that while the earth is applying a gravitational force to objects, they are applying the same force back to the earth (Newton's 3rd law, for every action there is an equal and opposite reaction). Its like if you push against a wall, the wall is pushing back just as hard. So how much force does the earth apply to the apple? The apple's weight, right? This means that the apple is applying exactly that much force right back to the earth!
So why do objects fall to the earth? Why doesn't the earth fall to the surface of the apple? Look at Newton's 2nd law: F = m*a
We now how much force is being applied to both the earth and the apple, but look at how different their masses are! For the above equation to stay true, a small mass combined with a large acceleration would give the same force as a large mass and a small acceleration. Since the earth's mass is enormous compared to the apple, its acceleration is so small that it can be neglected. The apple's small mass, however, can be accelerated quite easily with the amount of force available, so the apple falls to the earth.