The moon's distance from Earth is measured very accurately by bouncing a laser beam off of a small mirror left on the surface of the moon.If a laser is fired at the moon and the signal returns in 2.6 seconds,what is the distance to the moon? (Hint: speed of light c = 300,000 km/s)
A) 390,000 km
B) 390,000 m
C) 780,000 km
D) 780,000 m

Question

Quizplus · Accepted Answer

The round trip time for the laser is 2.6 seconds, so the one-way trip is 1.3 seconds. The distance is calculated as speed of light (300,000 km/s) multiplied by time (1.3 s), which equals 390,000 km.

The Moon's Distance from Earth Is Measured Very Accurately by Bouncing