Frank and Mary are twins. Mary jumps on a spaceship
and goes to the star system Alpha Centauri (4.30 lightyears
away) and returns. She travels at a speed of 0.8c
with respect to Earth and emits a radio signal every
week. Frank also sends out a radio signal to Mary once
a week. (a) How many signals does Mary receive from
Frank before she turns around? (b) At what time does
the frequency of signals Frank receives suddenly
change? How many signals has he received at this
time? (c) How many signals do Frank and Mary receive
for the entire trip?

Question

Frank and Mary are twins. Mary jumps on a spaceship
and goes to the star system Alpha Centauri (4.30 lightyears
away) and returns. She travels at a speed of 0.8c
with respect to Earth and emits a radio signal every
week. Frank also sends out a radio signal to Mary once
a week. (a) How many signals does Mary receive from
Frank before she turns around? (b) At what time does
the frequency of signals Frank receives suddenly
change? How many signals has he received at this
time? (c) How many signals do Frank and Mary receive
for the entire trip?

irishboy123 · Answer

have you any workings to show?

anonymous · Answer

i solved it! can i ask you another question?