The tip of a blade of an electric fan is 1.5 feet from the axis of rotation.If the fan spins at a full rate of 1760 revolutions per minute,how many miles will a point at the tip of a blade travel in an hour?(1 mile=5280 feet)
问题描述：
The tip of a blade of an electric fan is 1.5 feet from the axis of rotation.If the fan spins at a full rate of 1760 revolutions per minute,how many miles will a point at the tip of a blade travel in an hour?(1 mile=5280 feet)
答
blade末端绕一圈的行程是 2 • π • r ＝ 2 X 3.14 X 1760 ＝ 11052.8 feet
因为1分钟饶1760圈，1小时一共绕1760 X 60 圈 ＝ 105600 圈
这样 11052.8 X 105600 = 1167175680 feet， 因为1mile是5280 feet，所以1167175680 ／ 5280 ＝ 221056 miles
答
C=2*3.14*(1.5/5280)
S=1760*60*C
答
电风扇的顶部扇叶距离旋转轴1.5英尺,如果电风扇以每分钟1760最大的转速转动的话,那么电风扇顶部的扇叶在一小时内将会走过多少英里的路程.这样就很简单了,由题可以知道这个圆的半径就是1.5英尺,那么旋转一周的路程就...