How to Calculate the Period of Rotation
- 1). Determine how much the body has rotated in a given period of time. For example, assume that a planet or other spherical astronomical body has rotated 120 degrees in 15 hours.
- 2). Divide the number of degrees in a complete circle (360 degrees) by the number of degrees the planet has rotated. In the example above, dividing 360 degrees by 120 degrees gives 3. Call this result A.
- 3). Multiply result A by the time it took the planet to rotate the measured amount. Concluding the example, multiplying 3 by 15 hours gives 45 hours. This is the period of rotation of the planetary body.
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