Math 151, Workshop 81.A flagpole is 40 feet high and stands on level ground. Aflag is attached to a 120 foot rope passing through a pulleyat the top of the flagpole. The other end of the rope is tiedto a car at ground level. If the car is driving directly awayfrom the flagpole at 3 ft/sec, how fast is the flag risingwhen the top of the flag is 20 feet off the ground?Rr2.Two circles have the same center.The inner circle has radiusrwhich is increasing at the rate of 3 inches per second. The outercircle has radiusRwhich is increasing at the rate of 2 inches persecond. Suppose thatAis the area of the regionbetweenthe circles.At a certain time,ris 7 inches andRis 10 inches.What isAatthat time? How fast isAchanging at that time? IsAincreasing ordecreasing at that time?3.The numbersR1,R2,R3, andRsatisfy the following equation:1R1+1R2+1R3=1R.(The total resistanceR, of a circuit composed of parallel resistancesR1,R2, andR3.)a) IfR1= 1 andR2= 2 andR3= 3, computeRexactly.b) If bothR1andR3are held constant, andR2is increased by.05, what is the approximate
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