Part (b): We have to find the diameter of the nozzle if the speed of outcoming water is 21 m/s. If ‘r’ is the radius of the nozzle, then area of the cross-section of the nozzle will be A2 = πr2. For convenience, we put area of the pipe as A1 = π r12, where r1 = 0.048 m = radius of the cross-section of the pipe. Therefore,



Since diameter is 2 times the radius, therefore,

This is the answer.