STEPHEN 2.54

1. 1
 
 
 
2
A spaceship moves radially away
from Earth with acceleration 29.4
m/s about 3g . How much time
does it take for the sodium
streetlamps = 589 nm on Earth
to be invisible
with a powerful telescope to the

human eye of the astronauts? The
range of visible wavelengths
is about 400 to 700 nm.

2. 2
Solution

3. 3
0
0
0
Using
1
1
1
1
1
1
f
f
c
c








 




 


 


4. 4
0
2
0
2
1
1
1
[ ]
1
700 1
[ ]
589 1
1
1.41
1
1.41 1.41 1 0
0.41 2.41 0
0.17
nm
nm


 
 
 




 



 


 


 


 

    
  
 

5. 5
8
8
,
0.17
0.17
0.17 2.998 10
0.51 10
Now
v
c
v c
m
X X
s
m
X
s
  
 



6. 6
8
2
8
2
8
,
0.51 10
29.4
0.51 10
29.4
0.0173469 10 1734690
1734690
20.08
3600 24
f i
Now
v v
a
t
m
X
m s
s t
m
X
s
t
m
s
X s s
days days
X


 
 
 
 