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.
An inward net force is required to make a turn in a circle. This inward net force requirement is known as a centripetal force requirement. In the absence of any net force, an object in motion (such as the passenger) continues in motion in a straight line at constant speed. This is Newton's first law of motion.