A remote - sensing satellite of earth revolves in a  circular orbit at a height of 0.25 x 106 m above the surface of earth. It earth's radius is `6.38 xx 10^(6)m and g = 9.8 ms^(- 2)` , then the orbital speed of the satellite is ..........

Options

A. `6.67 kms^(-1)`
B. `7.76 kms^(-1)`
C. `8.56 kms^(-1)`
D. `9.13 kms^(-1)`

Answer

B

Explanation

`implies` For satellite revolves around earth,
`v_0 = sqrt((GM_e)/(Re+h))= sqrt((GMe)/(Re(1+h/(Re))))`
`:. v_0 = sqrt((gRe)/(1+h/(Re)))" " [ :. GM_e = gR_e^2]`
`:. v_0 = sqrt((9.8 xx6.38 xx10^6)/(1+(0.25xx10^6)/(6.38 xx 10^6)))`
`:. v_0 = sqrt(62.524 xx10^6)/(1.0392)`
`:. v_0 =sqrt(60.16 xx 10^6)`
`:. v_0 = 7.7566 xx 10^3 m//s`
`:. v_0 ~~ 7.76 kms^(-1)`