Question

A satellite revolving in a circular equatorial orbit from west to east appears over a certain point on the equator every 8 hours. Therefore it's period is

• A. 16 hr
• B. 8 hr
• C. 6 hr
• D. 32 hr

Answer 1

The correct option is C 6 hr


Earth rotates from $W\to E$
T = 24 hrs
$w_e=\frac{2\pi }{24}$
According to the information, the angular velocity of satellite with respect to the earth is $\frac{2\pi }{8}$
$w_s-w_e=\frac{2\pi }{8}$
$w_s=\frac{2\pi }{8}+\frac{2\pi }{24}$
$w_s=\frac{2\pi \times 4}{24}$
$w_s=\frac{2\pi }{6}$
$w_s=\frac{2\pi }{T}=\frac{2\pi }{6}$
T = 6 hrs