Can anyone answer this correctly I wonder?

Question

Hypothetically: A hole is drilled directly and perfectly from the north poll to the south poll. A metal ball weighing 5 kg is dropped at one end (lets say the north poll). Describe exactly what would happen to the ball?

(Ignore air resistance and the fact that the ball would melt due to temperature)

(and that the Earth is a perfect sphere, or atleast gravity is equal on all sides)

Interesting that noone has near mentioned a very crucial fact yet...

Answer 1

OMG, it would fall, go past the middle, then come straight back, repeat, repeat, repeat, ect. *sighs* some of these answers are ridiculous.
Send me a message if you have a question.

It's like a pendulum, it would go across Earth to the opposite point of where you dropped it from, and come right back to you, slowing acceleration at the middle, like said before by somebody else...

"it won't come out the other side for sure so it should stay at the center"
Yes it will.

These answers are going to make me cry...

Answer 2

What you get is a pendulum without any string attached. The ball would oscillate around the center of acceleration. The acceleration curve might be slightly different because it can't be reduced to a convenient point (gravity varies with the distance from the mass center - earth surface gravity depends among other factors on the density of the material below, which varies, and the distance from the center of the ellipsoid). In an ideal, atmosphere-less planet-sized iron ball with a perfectly drilled hole the pendulum should last until tidal effects slow it down.

Answer 3

You can't drill such a hole. Because the gravity will pull the crust and will reform it. May be the size of earth and its orbit will get changed. The only possible way of doing this is to pass a speeding object through earth's core which will have a force much stronger than earth's gravity and will go from south pole to north pole and emerge out with the same speed. The earth will break and reform instantly after that. So the question of droping a ball in such a earth means that the ball will go and stay in their at the center along with other things that get attaracted inside.

Answer 4

The ball will accelerate as it falls toward the center of the earth, but the rate of acceleration will decrease as the center is approached. Presently the ball will pass the center of the earth, going at considerable speed, and eventually wind up at the other side. The time from side to side will be about 90 minutes. The reason for the decreasing acceleration is that only the matter contained in a sphere centered at the earth's center and of radius of the ball's position has a net effect on it. (There is some fancy mathematics you can do to prove this.)

Answer 5

It would probably go in the whole and never come out or come out the same end you put the ball in.. due to the earths rotating axis and the amount of time it would take the ball to travel to the other side of the worldby the time it got some of the way down the hole, the earth would have turned..

Answer 6

the hole would fill in from the magma in the earth....
otherwise the ball would go out the other side come back out the whole it started and so on also the ball would srink as it got to the center do to the pressure also it would accelerate faster as it neared the center do to force of gravity= m1+m2/distance or somtin like that that is if the ball did not get stuck to the wall due to the magnetic feild also the gravity from other planets and celetial bodies would trow this off so we need to know the exact time

Answer 7

The gravitational force decreases as the ball approaches the center and becomes zero at the center; it increases as the other pole is reached. The force is always toward the center of the earth.

Under the action of such varying force it can be proved mathematically that the object will execute simple harmonic motion with the center of the earth as the equilibrium position.

The amplitude of motion is the radius of the earth.

Since there is no resistance the motion will be ever lasting. (To and fro motion)

Answer 8

I came across this question ,a few years ago and I was the quickest to solve that problem in my class.Well to cut the long story short , heres the answer,the ball reaches the centre of the earth ,at this pt the velocity is maximum and g(acceleration due to gravity) = 0.But the ball does not stop ,due to its inertia has enough energy to reach the other pole and resist the negative gravity.When it is at the other pole velocity = 0 .And since its velocity is zero , it should stop right? wrong , the ball changes direction and due to that the g becomes +ve maximum and it again reaches the centre and this process goes on and is thus harmonic

Answer 9

The ball will speed towards the center of the earth picking up speed due to the acceleration due to the gravity.

From the center it will move towards the opposite pole; but will be again pulled back towards the center and thus after oscillating on either side of the center, it will come to rest at the center of the earth. Like a pendulum comes to stop after oscillations.

Answer 10

The ball will accelerate and until it gets to the center. Then it will begin to decelerate until it just comes up out of the hole on the far side. If no one is there to catch it, then it will fall back into the hole to the opposite end and the whole process will start over again.

This ignores outside affects as you suggested.