【英语时差8,16】向心力与头晕-下（在线收听）

 A force is required for an object to move in a circle, as is the case with a merry-go-round. This force is called a centripetal force. Generally speaking, the larger the circle you move in, the greater the centripetal force you experience.So, the farther you move away from the center of the merry-go-round, the more force the merry-go-round must exert on you to keep you moving in that circle. All this extra force on your inner ear can make you lose your balance and feel quite dizzy. Another way to see centripetal force in action is with an old-fashioned record player. Place a penny near the center of a spinning record, and it will stay in place as it turns.Put the penny on the edge, however, and it will fly off the record, giving visible proof that the force at the edge of a spinning object is greater than at the center.