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Quiz8_Physics241_S09 - Sally measures the time between her...

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----- Quiz 8- 15 April 2009 Name: -----.<'------ Recitation Day/Time 1. Sam travels at very high speed to a distant star Alpha, which is exactly 8.0 light- years away from Earth. As soon as he safely arrives at Alpha, he sends a radio signal back to his girl-friend Sally who remained behind on Earth. The signal arrives at Earth exactly 18.0 years after the left. a. At what speed did he travel to Alpha? (2 points) b. According to Sam, how long did it take for him to reach Alpha? (3 points) (q) £&(df'o !'1'Jft41 J4-b s , 'fur!' +r~vt-III~ a-f flu $fu) tJ! ILjhf It; nA~tt EtVr'1it. . - . 1htl~ S~tAIl ~ (18 -e-) :: Ie J Iv ~dt.. AI r4..Q vet = ~ .:: o .. g.c [b) 1ft -f~ I:~~ bvr.fh qLA/Y~ Iv Ylj)fdL~. - /0 J( /) /ItA jJJ1Jj bY 'It ~ LJt~ J=: LJt? d = 10. t:Jj 1..:.(~t:)2 - . G
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Unformatted text preview: Sally measures the time between her successive heartbeats to be 1.09s.1f she is t:Jt () =: ~. () Cf~ travelling at 0.90c relative to an observer on Earth, find the time between beats ..j according to the same observer. (3 points) ,{c,/I J hA.s fWfbr liut.t LJt o = /. . oCfS t!J t 0 ~ to / ., tJ r -:<.,5~' J 1 _("-:C) 2 3. A space-craft flying above the Earth's surface at a speed ofO.9c is measured to have a length of 30 m according to an observer stationary on the Earth. What would be the length of the space-craft according to the same observer when it comes to rest on the Earth's surface? LeuJfl-t of mov/nJ SjJcue-cr4fl _ L ::: 30m Proper L enJfh L o :: 7f L := Eo :::===== :: l' _(O~qCf2 L = Lo/y 6t = y6to C = 3.0x10 8 rn/s...
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