Seville has the only inland port in Spain, located 80 km (50 mi) from the mouth of the Guadalquivir River. This harbour complex offers access to the Atlantic and the Mediterranean, and allows trade in goods between the south of Spain (Andalusia, Extremadura) and Europe, the Middle East and North Africa.
Centripetal force. The centripetal force is the force that causes an object to move in a circle, acting towards the centre of the circle. In the case of a satellite the centripetal force is gravity, in the case of an object at the end of a rope, the centripetal force is the tension of the rope.
Centrifugal force is the force which describes the outward pressure that is exhibited around an object rotating around a central point. Its definition is based on a Latin phrase which means fleeing the center, an accurate description based on what is being observed. There are some physicists who claim that true centrifugal forces do not exist, that an object's reaction to such a force can be explained by other means.