rguig (tr7356) – Homework 12 – yao – (59020)
1
This
printout
should
have
20
questions.
Multiplechoice questions may continue on
the next column or page – find all choices
before answering.
001
10.0points
The operator of a space station observes a
space vehicle approaching at a constant speed
v
. The operator sends a light signal at speed
c
toward the space vehicle.
What is the speed of the light signal relative
to the space vehicle?
earthbound observer will seem greater than
the lifetime seen by an observer moving with
the muon. Using the time dilation equation,
T
=
T
0
radicalbigg
2
1.
c
correct
2.
c
radicalbigg
1

v
2
c
2
3.
v
radicalbigg
1

v
2
c
2
4.
c
+
v
5.
c

v
= 3585 s
.
What is the lifetime of this muon as mea
sured by an observer on the Earth?
The lifetime of the muon as seen by the
earthbound observer will seem greater than
the lifetime seen by an observer moving with
the muon. Using the time dilation equation,
T
=
T
0
radicalbigg
2
003
10.0points
Find the speed relative to Earth of a uni
formly moving spaceship whose clock runs 15
s slow per hour compared with an Earthbased
clock.
T
= 3585 s
.
rguig (tr7356) – Homework 12 – yao – (59020)
2
2.
Length contraction reduces the apparent
length.
correct
3.
Time dilation makes the lifetime of elec
trons longer.
4.
Electrons travel faster than the speed of
light.
Explanation:
For the moving electron, length contraction
reduces the apparent length of the 2mile long
tube.
Since electrons move with nearly the
speed of light, the contraction is very signifi
cant.
keywords:
005
10.0points
A spaceship is measured to be 158 m long
while at rest relative to the observer.