Q: If you could drill a tunnel through the whole planet and then jumped down this tunnel...

ask a mathematician dot com ^ | 4-2014 (orig 2012) | physicist

[gorush]

I concur.

[Vinnie]

You accelerate all the way to the center then begin to slow as you pass it. You slow to the apex right at the surface on the other side.

That was my thought also.
Kinda like stepping on an elevator on the ground floor and stepping off on the 26th floor.

[Hoodat]

Holy crap! This is the (in)famous spring equation, F = – kx!

Robert Hooke is one of the greatest scientific minds ever.

[central_va]

If you are in a free falling elevator would jumping up at the very end, just before impact, save your life?

[Lonesome in Massachussets]

No two vertical lines are parallel as a plumb line always points to the center of the earth.

Laplace would be surprised to hear that. That is true on a spherical planet, and on an ellipsoid of rotation, only on the equator and at the poles. It's complicated.

[skinkinthegrass]

"diggin' to China"or just tell him, "It's a fallout shelter, Dad..just thinkin' of the
future w/Jimmah "Malaise" Carter"..(now w/0'Muslim)

[ThomasThomas]

They can’t get permits to build the keystone pipeline.

[MV=PY]

He’s assuming there is a vacuum in the hole. You would not reach terminal velocity because there would be no air resistance.

You would accelerate all the way to the center, so you’d get moving pretty fast.

However, acceleration due to gravity would steadily decrease as you approach the center. Your momentum would carry you through the center, then you begin decelerating.

[SamAdams76]

When I was about 8 years old, my friends and I decided that we would dig a hole to China. We were serious. We actually thought that if we were determined enough, and gave up watching Speed Racer and Gilligan's Island on the TV, that our perseverance would pay off and our shovels would eventually strike daylight and we'd emerge into a world of smiling Chinese people with fortune cookies, rice paddies and beef teriyaki on a stick (our favorite).

With great enthusiasm, we proceeded to start the hole - in my backyard, because other parents wouldn't let their kids dig in theirs - and after the first afternoon of digging, we actually had a pretty decent sized hole with mounds of dirt and rocks all around.

The next morning, I was woken up to the sounds of my father shouting for me. I came downstairs and my mother grabbed me by the hair and shoved me to the floor in front of my glowering father whose face was rapidly turning a deep shade of red. He simply pointed to the backyard and said "fill it" and walked away.

None of my friends came over to help me fill it. It took pretty much all morning and sure enough, there was not enough dirt to completely fill it and even to this day, some 40 years later, there is still a slight depression in the yard where the aborted hole to China lies unfinished.

[Lonesome in Massachussets]

http://en.wikipedia.org/wiki/Schuler_tuning

It’s the same period as the period of a satellite orbiting the earth just above the surface.

[GeronL]

Someone answering an old qyestion with real science- such a spoil sport - lol

[Delta Dawn]

I bet you have more stories to tell... :)

[cripplecreek]

As I understand it, it wouldn’t even need to be directly through the center of the earth. Basically you could drill a straight tunnel (through the curvature of the earth) from LA to NY and get the same effect.

I watch a lot of science shows.

[chajin]

Then you have to fill it in without the help of the neighborhood kids who were helping you dig to China in the first place.

But you don't have to dig to China, just go in the kitchen and open the cabinet doors.

[chajin]

Cosine, it’s worth pointing out, is sinusoidal.

Does that explain why Howard Cosine had such a big nose?

[Hoodat]

You accelerate all the way to the center then begin to slow as you pass it.

Correct. Maximum velocity would be achieved as the object passes through the center. The maximum rate of acceleration (from x to y) would be realized at the start. The initial acceleration would be 9.8 m/s². At the earth's center, it would be zero, and at the opposite end of the earth, it would be -9.8 m/s².

The object would not begin to slow until acceleration goes negative which would occur just after passing through the center point.

[central_va]

Cosines include an angle that’s a-cutie.

[Hoodat]

I had figured that after digging such a hole, I would end up putting a drain in the Indian Ocean which would result in flooding my entire town. Needless to say, that dissuaded me from putting forth the effort.

[cripplecreek]

Also, down would be come up as you passed the center.

[IronJack]

You would achieve enough momentum to carry you past the point of zero gravity (the center), so that you would "fall upward" for a ways. Then you would lose the momentum and fall back, with slightly less energy until you passed the center going the other way, then you would oscillate back and forth before eventually coming to a stop at the equilibrium point -- the center.

I asked this same question to a physics instructor when I was going to college.