Answer:
A. [tex]93[/tex] min
Explanation:
[tex]M[/tex] = mass of earth = 6.0 x 10²⁴ kg
[tex]R[/tex] = Radius of earth = 6400 km = 6.4 x 10⁶ m
[tex]h[/tex] = Altitude above earth = 400 km = 0.4 x 10⁶ m
Radius of orbit of the space station around earth is given as
[tex]r = R + h[/tex]
[tex]r = 6400 + 400[/tex]
[tex]r = 6800[/tex] km
[tex]r = 6.8 \times 10^{6}[/tex] m
[tex]T[/tex] = Time period of orbit of space station
Here we can use Kepler's third law which is given as
[tex]T^{2} = \frac{4\pi ^{2} r^{3}}{GM}[/tex]
Inserting the above values
[tex]T^{2} = \frac{4(3.14)^{2} (6.8\times10^{6})^{3}}{(6.67\times10^{-11})(6.0\times10^{24})}[/tex]
[tex]T^{2} = 3.1\times 10^{7}[/tex]
[tex]T = 5566.53[/tex] sec
[tex]T = 5566.53 \left ( \frac{1min}{60sec} \right )= 93 min[/tex]