IF there was a hole going through the diameter of the Earth, what would happen to an object that fell into it?

Question

Ignore the core temperature of the Earth.

Answer 1

It would be held in the center

Answer 2

This very same question must have been asked hundreds of times on Yahoo Answer, and I've answered this several times.

The answer is that if you can ignore the high temperature of the Earth's core, then an object thrown down a hole that goes throught the diameter of the Earth to the other side will oscillate back and forth from one hole openning to the other hole openning. That's also assuming that there is NO air resistence, but if there is, then eventually the oscillations gets smaller and smaller until the object become motionless at the center of the Earth.

Answer 3

The gravitational force at any point is proportional to the square of the distance from the centre of the earth. So the force decreases as you get towards the centre, and your acceleration drops towards zero, but you continue to travel at a more or less constant speed through the core, then start decelerating as you fall "upwards" towards the other side.

Note this is not Simple Harmonic Motion as some others have said. This relies on the force increasing LINEARLY with distance from the centre (e.g. Hooke's Law for springs). The force in this case increases as the SQUARE of distance.

If there was no air resistance, you'd just get to the surface on the far side before falling back again, oscillating from one side to the other. Since the hole would be full of air though, you'd slow down on each pass, so you wouldn't quite get as near to the surface each time and would eventually end up in the centre. You'd have a long climb back out.

Also note that, unless the hole was drilled down the rotational axis of the earth, you'd hit the side of the hole as you fell!! Imagine you're standing still on the equator, the earth's surface and you are travelling "East" at 1000 mph. Now step into the hole. You'd continue to travel "East" at 1000mph, but as you approach the earth's centre, the hole is moving "East" more slowly (500mph half-way to the centre for example, and not at all in the centre), so you'd be bouncing down the side of the hole all the way down. Ouch!

Answer 4

Assuming no air resistance it would oscillate around the center of earth in simple harmonic motion(force of gravity always directed to wards the center causes SHM) infinitely. If there is air resistance the oscillations would get dampened gradually and object would come to rest at the center of Earth.

Answer 5

If there was no air resistance, the object would gain enough velocity to just make it through to the far side before coming back and then just making it back to where it started before oscillating backwards and forwards forever. If there was air resistance in the tunnel, the oscillation amplitude will decrease each pass and the object would eventually come to rest at the centre.

Answer 6

it would oscillate between both end of the hole. as the speed of the object would make it possible for the object to pass throught the center, but when arrive at the other end the gravitation force will be too strong and the object will fall again....... and so on

Answer 7

Ultimately the object will be at the center of the Earth but who will drill the hole & how?

Answer 8

I just love those answers. They get so serious and all. Lemme'
ask, if there was a hole going through the center of your head, ignoring your body temperature, and if it was big enough, and I threw a Frisbee at you.............................

Answer 9

it would stop at the centre of the core, as the focus of gravity is here

Answer 10

It must burn up when it reaches the core