If it was possible and you could dig a tunnel from the top of the earth to the bottom of the earth and dropped a stone down it what would happen to the stone would it shoot up out of the hole or something else? please help this is driving me nuts.
This has been asked many time previously. The consensus is that the object would accelerate until reaching the center of the earth, then decellerate, coming to a stop and again accelerating towards the center of the Earth in the opposite direction, until the oscillations stop and the object comes to rest in the center...
Assuming you mean a tunnel through the centre of the Earth to emerge the other side then the stone would fall through the hole and past the centre where it would eventually be arrested by gravity when it would fall towards the centre again and so on. It would continue oscilating this way until it came to rest at the centre.