Explain why the size of the needle of a syringe controls flow rate better than the thumb pressure exerted by a doctor while administering an injection
For a constant height, the Bernoulli’s theorem is expressed as, P+ 1 2 ρ v 2 =constant In this equation, the pressure P occurs with a single power whereas the velocity occurs with a square power. Therefore, the velocity has more effect compared to the pressure. For this reason needle of the syringe controls flow rate better than the thumb pressure exerted by the doctor.
