班級:光電二乙 姓名:曾瀚緯 學號:497L0114
Ch1
4.An observer on a spacecraft moving at
finds that a car takes 40.0min to make
to the driver of the car？
解：
t=
v=0.7c
2400=
t=40min=2400sec
2400=
2400
2400=
to=
0.700C relative to the earth
a trip.How does the trip take
23.A woman leaves the earth in a spacecraft that makes a round trip to the nearest start，
4light-years distant，at a speed of 0.9C . How much younger is she upon her return than
her twin sister who remained behind？
設雙胞胎都是十歲，而她的雙胞胎姐妹在地球等了 X 年，女人來回總共坐了 8 光年
V=0.9c
L0=4light-years
L=L0
=4
=0.434(比例)
=
=
=0.434
X=0.92(地球上經過的時間)
9.092
33.A particle has a kinetic energy 20 times its rest energy. Find the speed of the
particle in terms of C.
mc 2 ×20＝（r－1）mc 2 ，r＝21
21＝
1
1
V2
C2
，
1
2 110
V
＝ 1 2 ＝
＝0.9988655697，V＝0.9988655697C
21
C
21