An astronaut is approaching the moon. He sends a ratio signal of frequency `5 xx 10^(9) Hz` and find that the frequency shift in echo received is `10^(3) Hz`. Find his speed of approach.

Explanation

Frequency of reflected signal
`v' = v(1 + (2 v)/(c ))`
`(Delta v)/(v) = 2 (v)/(c )`
`(10^(3))/(5 xx 10^(9)) = (2 v)/(3 xx 10^(8))`
`v = 30 m//s`