Earth's+Rotation

The rotation speed of the earth depends on where you happen to be. If you stand directly on the north or south pole, it is essentially zero. After 24 hours you would have rotated one complete turn and be facing the way you started. There is no tangential speed. At the equator - where one would travel one complete lap of the earth in 24 hours - your speed would be about 1000 miles per hour. (assuming a 24000 mile circumference for the earth). As you travel north or south from the equator towards the poles your tangential speed decreases. It is a bit like a carnival ride.

The answer from trigonometry is C = 2 x Pi x R x Cos((Pi x L)/180), where C is the circumference in miles, Pi is 3.141592653..., R is the radius of the Earth, which is 3963 miles, and L is the latitude in degrees (for example Los Angeles is at latitude 34 degrees North).

Hence if you live in Los Angeles, you go around in a circle 2 x Pi x R x Cos(Pi x 34/180) = 20643 miles in circumference each 24 hours, which means you are speeding along at 20643/24 = 860 miles/hour.

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