How fast is the Moon moving as it orbits Earth? For reference, the Moon's orbit is approximately circular with a radius equal to 400,000 km, and the Moon's orbital period is 27 days.
A) 1 km/s
B) 10 km/s
C) 50 km/s
D) 100 km/s
E) 500 km/s

Question

Quizplus · Accepted Answer

The Moon's orbital speed can be calculated using the formula for the circumference of a circle (2πr) and dividing by the orbital period. The circumference is approximately 2,512,000 km (2 * π * 400,000 km), and dividing by the period (27 days or 2,332,800 seconds) gives a speed of about 1 km/s.

How Fast Is the Moon Moving as It Orbits Earth