The of Earth is the cause of the cycle of day and night on Earth.
revolution
rotation
orbit
Earth rotates on its own axis towards the east making one half at one instance illuminated (day) and other dark (night).
A satellite moves round the earth in a circular orbit of radius R making one revolution per day. A second satellite moving in a circular orbit, moves round the wrath once in 8 days. The radius of the orbit of the of the second satellite is?