I'm trying to understand the basics of gravity. Newtons law of universal gravitation gives us : F1 = F2 = G (m1m2)/r2 Now on earth you can simply that down to F = mg where g = G (mearth/R2) But using f = mg, a heavier object say a tennis ball should fall faster than a cannon ball. But it doesn't because for some reason acceleration due to gravity on earth is about 9.857 ms, regardless of how heavy your object is. This doesn't make much mathematical sense to me since the force of gravity is F = mg where m is the mass off the falling object, so a heavier object should fall quite faster ! Can someone please show me the step I'm missing here?