A gardener waters the plants by a pipe of diameter 1mm. The water comes out at the rate or 10 cm3s.The reactionary force exerted on the hand of the gardener is

Rate of flow of water Vt=10 cm3sec=10×10−6m3secDensity of water ρ=103kgm3Cross-sectional area of pipe A=π(0.5×10−3)2Force =mdvdt=mvt=Vρvt=ρVt×VAt=Vt2ρA                                                            ∵ v=VAtBy substituting the value in the above formula we get F=0.127N