Question

When the Voyager 2 spacecraft sent back pictures of Neptune during its flyby of that planet in 1989, the spacecraft’s radio signals traveled for 4 hours at the speed of light to reach the Earth. How far away was the spacecraft? Give your answer in astronomical units (AU). (2 points) When Mars and Earth are at their minimum separation from each other, they are 0.36 AU apart. How long would it take a radio signal sent from Earth to reach Mars? Give your answer in minutes.

Answer 1

Answer:

a) 28877 AU

b) 1.795 sec

Explanation:

Time it took the radio signal to reach earth = 4 hours = 4 x 3600 = 14400 s

speed of radio signal = speed of vacuum speed of light  = 3 x 10^8 m/s

Distance traveled by this signal = speed x time

distance = 3 x 10^8 x 14400 = 4.32 x 10^12 m

One Astronomic unit AU is the distance between the Earth and the sun and it is approximately equal to 1.496 x 10^8 m

The distance traveled by the signal in AU = (4.32 x 10^12)/(1.496 x 10^8) = 28877 AU

b) The minimum separation between Earth and Mars = 0.36 AU

This distance = 0.36 x 1.496 x 10^8 = 538560000 m

Time that will be taken for a radio signal to travel this distance = distance/speed

==> 538560000/(3 x 10^8) = 1.795 sec