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Q & A: tunnel through the Earth

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Most recent answer: 01/09/2019
Q:
Thought experiment. Assuming I could drill a tunnel straight through the diameter of the earth. Lets assume this tunnel provides sufficient insulation and is pressure proof. If I step into the tunnel what would happen? Assuming I'm not burnt to a crisp or run out of air. Would I shoot out of the tunnel at terminal velocity fly into the air and land with a splat? or would gravitational forces stop me in the middle of the tunnel?Thanks in anticipation.
- Keith Wright (age 70)
Ottawa, Ontario, Canada
A:

In the simplest idealized picture you describe, you'd reach a maximum speed as you passed the center of the Earth, then slow down and reach zero speed as you reached the opposite surface. Then you'd reverse the trip and bounce back and forth. If the Earth's density were uniform, the motion would be sinusoidal, just like a mass bouncing on an ideal spring. The round trip time is around 90 minutes.

Mike W.


(published on 01/09/2019)

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