Strange question

walker

So I came across a question in a quiz book the other day and I still haven't been able to answer it, so I figured I would ask some experts... Here goes...

As a NASA senior physicist, would you agree with the calculation made by a junior physicist regarding the speed of an artificial satellite, v = 3 x 10^4 m/s, assuming that it is travelling at an altitude h = 230 km above the earth's surface where g = 9.0 m/s^2. The radius of the earth is 6370 km.

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chroot

Staff Emeritus
Gold Member
I would disagree.

For all circular motion, a = v2/r, where a is the centripetal acceleration, v is the linear velocity, and r is the radius of the circle.

Plug the numbers in, and you'll see there's a contradiction.

The satellite should be moving at roughly 7,000 m/s, not 30,000 m/s.

For more info on circular motion: http://hyperphysics.phy-astr.gsu.edu/hbase/circ.html#circ

- Warren

enigma

Staff Emeritus
Gold Member
Yep,

If the sat is going at that speed and altitude, it won't be at that altitude for long.

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