Why is the needle of syringe sharp ?
Explain why the tip of a sewing needle is sharp.
Why should we pivot the compass needle on a sharp pin?
A piston of a syringe pushes a liquid with a speed of 1 cm/sec. The radii of the syringe tube and the needle are R = 1cm and r = 0.5 mm respectively. The velocity of the liquid coming out of the needle is