Calculate the percentage of reduction for copper wire if its

Calculate the percentage of reduction for copper wire, if its initial diameter was 4 mm and final diamtere was 1 mm. Find the ratio between entry and exit velocities.

Solution

Percentage reductoin = ((Inital area-final area of wire)/intial area)*100

= [(Ain -Af)/Ain]*100

= [(Di- Df)/Di]*100

= [(4-1)/4]*100

= 75%

b) we know that Vi *Di² = Vf *Df²

Vi/Vf = (Df/Di)²

  = (1/4)²

  = 0.0625