Hi, I'm currently studying Physics for my GCSEs and I'm revising for them but the text books only explain what happens but not why. I know that centripetal force is the force requirement for an object to move round in a circle. But I don't see why this is the case for satellites orbitting the earth. The gravity is pulling the object inwards yet the object moves in a circle... why is this? The satellite is moving at a steady speed which keeps it following the orbit path but is there anything that caused this speed initiate? Because when someone jumps off a building they'll fall straight to the ground rather than orbit the earth at high speed.