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posted by  strongba on 8/29/2008 6:31:26 PM  |  status: Live  

Physics Prob#4..

Course Textbook Chapter Problem
General Physics N/A N/A N/A
Question Details:
How long did it take for a message sent from Earth to reach the first astronauts on the Moon?
..in seconds
 
How long will it take for a message from Earth to reach the first astronauts who arrive on Jupiter; assume Jupiter is at its closest approach to Earth (629 multiplied by 106 km)?
..in min
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Oracle
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posted by Roger Bravo on 8/29/2008 6:47:49 PM  |  status: Live
Asker's Rating: Lifesaver   
strongba's comment:
"Thanks, again!!!"
Response Details:
 
   Distance travelled   =   velocity * time
 
   d   =   v * t
 
   velocity of signal ( radio waves)   =   3.0 * 108 m/s
 
   1.   distance to moon   =   3.84 * 108  m
 
   time   t   =   3.84 * 108  m / 3.0 * 108   =   1.28 s
 
   2.   distance to jupiter   =   629 * 106   km   =   6.29 * 1011   m
 
   time   T   =   6.29 * 1011   m /  3.0 * 108 m/s
 
      T   =   2.097 * 103   s   =   2.097 * 103 / 60   =   34.94   min
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posted by mohit on 8/29/2008 6:51:57 PM  |  status: Live
Asker's Rating: Helpful   
Response Details:
  time  =  dist / speed  =  629 x 106  km  /   3 x 105  km/sec  =  2.096 x 103  seconds  which is about  35 minutes
 
Sage
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posted by YAH00.com on 8/30/2008 7:48:22 AM  |  status: Live
Asker's Rating: Helpful   
strongba's comment:
"thanks..very simple...now"
Response Details:
1)

use the formula: distance = velocity X time

time = distance/velocity
time = 3.84 X 108  m / 3.0 * 108 m/s
time = 1.28 seconds


2)

use the formula: time = distance/velocity

time = 6.29 X 1011  / 3.0 X 108 m/s
time = 2.097 X 103   seconds
time = 35 minutes
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