p34_001

# p34_001 - . (c) We take d to be 2(1 . 3 10 9 km) = 2 . 6 10...

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1. The time for light to travel a distance d in free space is t = d/c ,where c is the speed of light (3 . 00 × 10 8 m / s). (a) We take d to be 150 km = 150 × 10 3 m. Then, t = d c = 150 × 10 3 m 3 . 00 × 10 8 m / s =5 . 00 × 10 4 s . (b) At full moon, the Moon and Sun are on opposite sides of Earth, so the distance traveled by the light is d =(1 . 5 × 10 8 km) + 2(3 . 8 × 10 5 km) = 1 . 51 × 10 8 km = 1 . 51 × 10 11 m. The time taken by light to travel this distance is t = d c = 1 . 51 × 10 11 m 3 . 00 × 10 8 m / s = 500 s = 8 . 4m
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Unformatted text preview: . (c) We take d to be 2(1 . 3 10 9 km) = 2 . 6 10 12 m. Then, t = d c = 2 . 6 10 12 m 3 . 00 10 8 m / s = 8 . 7 10 3 s = 2 . 4 h . (d) We take d to be 6500 ly and the speed of light to be 1 . 00 ly / y. Then, t = d c = 6500 ly 1 . 00 ly / y = 6500 y . The explosion took place in the year 1054 6500 = 5446 or 5446 BCE....
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## This note was uploaded on 11/12/2011 for the course PHYS 2001 taught by Professor Sprunger during the Fall '08 term at LSU.

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