# physics

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The average speed of an orbiting space shuttle is 20100 mi/h. The shuttle is orbiting about 196 mi above the Earth’s surface. Assume the Earth’s radius is 3963 mi.

How long does it take to circle the Earth? Answer in units of h ( hours)

• physics - ,

I am not providing further assistance unless you show work. Start by calculating the circumference of the orbit.

• physics - ,

Time = orbit circumference divided by speed.

It might be of some interest to you is the fact that a spacecraft's orbital speed at 196 miles altitude is
V = sqrt[1.407974x10^16/(3963+196)(5280)] = 25,321fps = 17,265mph.

• physics - ,

So would I take the answer from the formula for a circumference of a circle(24900.26337) and divide it by 17,265 to get 1.442239408(~1.44h)?

How I got the circumference: 2 x pi x 3963=24900.26337

• physics - ,

Yes, that is correct, but I would verify the units. radius is in miles, so circumference is in miles, speed is in miles per hour, so time is in hours.

• physics - ,

I tried 1.44 h, but I got the answer wrong. Can you please tell me what I may be doing incorrectly with the significant figures? thanks

• physics - ,

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