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RE: RE: RE: This A Different Message

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Posted by Michael Wright on October 17, 2000 07:39:51 UTC

Just a few comments...

Work = Force x Distance

this is not just any ole distance, though.
When you pass your hand over a mug, you are NOT doing work, because the net force in the y-direction (the direction affected by gravity) = 0. If you raise or lower your hand above the mug you are performing work, though, because there is a net force moving a distance.

You do have to perform work to escape from a black hole. To simplify the problem, let`s turn this into a 2-D problem just as the hand-over-mug problem is.
-As you roll around the bowl trying to escape the black hole, pulling away as you said, the absolute value of the distance from the center of the black hole`s mass increases.
-Your angular velocity does not matter in this problem; it is the same as moving your hand across the mug. Your velocity away from the black hole, away from the direction of the centripetal acceleration (just as raising your hand up away from the mug goes away from the direction of the acceleration due to gravity) is increasing. This means that work is being done.

In other words, you have to climb out of the gravity well of the black hole.

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