Answer:
v = 7671.57 m/s
T = 1.55 hours
Explanation:
mass of Earth, M = 6 x 10^24 kg
Radius of earth, R = 6400 km = 6.4 x 10^6 m
height, h = 400 km
Velocity is given by
[tex]v=\sqrt{\frac{GM}{R+h}}[/tex]
where, G be the universal gravitational constant.
G = 6.657 x 10^-11 Nm^2/kg^2
[tex]v=\sqrt{\frac{6.67\times 10^{-11}\times 6\times 10^{24}}{6800\times 10^{3}}}[/tex]
v = 7671.57 m/s
Let T b the period
[tex]T=\frac{2\pi (R+h)}{v}[/tex]
[tex]T=\frac{2\times 3.14(6800\times 1000)}{7671.57}[/tex]
T = 5566.53 second
T = 1.55 hours