A gardener is watering plants at the rate 0.1 litre/sec using a pipe of cross - section 1 cm^(2). What additional force he has to exert if he desires to increasethe rate of watering two times ?

A gardener is watering plants at the rate 0.1 litre/sec using a pipe o

1.	A gardener is watering plants at the rate 0.1 litre/sec using a pipe of cross - section 1 cm^(2). What additional force he has to exert if he desires to increasethe rate of watering two times ?
Answer» Solution :`F=Adv^(2)=((Av)^(2)d)/(A)` If rate of watering plant (Av) is doubled, it means amount of water poured / sec is doubled which is possible only if velocity is doubled. Hence force is to be made 4 TIME. `THEREFORE` additional force = 3 TIMES initial force `= 3Adv^(2)=3((Av)^(2))/(A)d` `= (3xx0.1xx0.1xx10^(3))/(10^(-4))=3xx10^(5)N`