An artificial satellite is moving in a circular orbit of radius 42250 km.  Calculate its speed if it takes 24 hours to revolve around the earth.

Answer: 

Radius of orbit = 42250 km

 Distance travelled in 1 revolution = Circumference of orbit=2πr  =2 × 22 / 7 × 42250 

=265571.42 km

Time = 24 hours 

Speed = Distance travelled / time taken

 = 265571.42 / 24 =11065.47 km/h

Therefore, the satellite orbits at a speed of 11065.47 km/h.