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Motion In Straight Line

Question
CBSEENPH11017852

Calculate the velocity of an atmospheric particle 1600 km above the earth's surface, given that the radius of the earth is 6400 km and acceleration due to gravity on the surface of the earth is 9.8 m/s2.

Solution

We have, 
h = 1600 km 
R = 6400 km = 6.4 x 106
Therefore, 
r = R + h = 6400 +1600
  = 8000 m = 8.0 x 106 m
 
Hence, escape velocity is given by,
straight v subscript straight e space equals space square root of 2 space straight g apostrophe straight r end root space equals space square root of 2 open parentheses gR squared over straight r squared close parentheses straight r end root space

space space space space space equals space square root of fraction numerator 2 space gR squared over denominator straight r end fraction end root space equals space square root of fraction numerator 2 straight x 9.8 space straight x space left parenthesis 6.4 space straight x space 10 to the power of 6 right parenthesis squared over denominator 8 space straight x space 10 to the power of 6 end fraction end root

space space space space space equals space 10.02 space straight x space 10 cubed space straight m divided by straight s