Figure shows a liquid being pushed out of a tube by pressing a piston. The area of cross section of the piston is 1.0 cm^2 and that of the tube at the outlet is `20 mm^2`. If the piston is pushed at a speed of `2cms^-1`. What is the speed of the outgoing liquid?

Explanation

From the equation of continuity
`A_1v_1=A_2v_2`
or `(1.0cm^2)(2cms^-1)=(20mm^2)v_2`
`or v_2=(1.0cm^2)/(20mm^2)xxcms^-1`
`=(100mm^2)/(20mm^2)xx2cms^-1=10cms^-1`