How many kilometers per hour does the moon move?

Answer 1

Without even looking up the moon's orbital speed, we can rough it out by using

a few numbers that we already know, and the answer ought to be close enough

for most purposes.

First, note that any speed, or any velocity for that matter, is always relative to

something. Along with the earth, the moon is in an annual 93-million-mile orbit

around the sun, but we're going to ignore that motion, and calculate the moon's

speed relative to the earth.

The average earth-moon distance is 383,000 kilometers. If we assume the moon's

orbit to be circular, then the circumference of that circle is the total length of the

moon's orbit. That's (2 pi) x (radius) = 766,000 pi kilometers.

Speed = (distance)/(time). The moon completes one orbit around the earth in 27.32 days,

and each day is 24 hours. That's all we need.

Speed = (766,000 pi) / (27.32 x 24) = 3,670kilometers per hour = 2,280 miles per hour (rounded)