Question

A pool has a uniform circular cross section of radius 5 metre and uniform depth1.4m . it is filled by pipe which delivers water 20 litre per second calculate in minute the time taken to fill the pool.if the pool is emptied in 42 minute by another cylindrical pipe through which the water flows at 2 metre per second .calculate the radius of the pipe in centimetre​

Answer 1

Answer:

Step-by-step explanation:

begin mathsize 16px style Volume space of space the space pool equals πr squared straight h

equals 22 over 7 cross times 5 squared cross times 1.4

equals 110 space straight m cubed

20 space litres equals 0.02 space straight m cubed divided by sec

Time space taken space to space fill space the space pool equals fraction numerator 110 over denominator 0.02 end fraction equals 5500 space sec equals 5500 over 60 equals 275 over 3 minutes equals 91 2 over 3 minutes

Let space the space radius space of space the space outlet space pipe space be space straight r space straight m

42 space minutes equals 42 cross times 60 equals 2520 space sec

Time space taken space to space fill space the space tank equals fraction numerator 110 over denominator 2 cross times πr squared end fraction

rightwards double arrow 2520 equals fraction numerator 110 over denominator 2 cross times πr squared end fraction

rightwards double arrow straight r squared equals fraction numerator 110 cross times 7 over denominator 2520 cross times 2 cross times 22 end fraction

rightwards double arrow straight r squared equals 1 over 144

therefore straight r equals 1 over 12 straight m

Radius space of space the space pipe equals 1 over 12 cross times 100 equals 25 over 3 cm end style