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.
The centripetal force (Fc) furnished by the weight (wt) of the suspended masses is now keeping the stopper moving in a circular path of fixed radius. It is important to keep two factors constant during the course of this exercise: the mass of the orbiting object and the radius of the orbit. The centripetal force is varied by altering the amount of mass suspended from the string. Note that the mass of the rubber stopper is 0.0045 kg and the mass of the cord is neglected.