Question

The distance from Earth to the Moon is approximately 240,000 mi.. The speed of light is 3.00 * 10^8 m/s. How long does it take for light to travel from Earth to the Moon and back again?. Please Show work.

Answer 1

First we have to convert miles to meters:
1 mile ≈ 1,609.34 m
Time of traveling one way:
$t = \frac{240,000 * 1,609.34m}{3.00*10^{8}m/s } = \\ = \frac{8*10 ^{4} *1,609.34s}{10 ^{8} } = \frac{8*1,609.34 s}{10,000}$ = 1.28 s
From Earth to the Moon and back time is:   2 · 1.28 s = 2.56 s