You have a syringe which is filled with 10 ml of water.
The inner diameter of the main body of the syringe is 15.9 mm, and the inner
the diameter of the outlet is 1.2 mm. With how much force you have to press
the plunger for clearing the syringe for water within 10
Seconds? You can overlook the friction of the piston and the viscosity of the water.
Now place a needle on the syringe, with a length of 25 mm and inner diameter
0.210 mm. If you press the plunger with the force 0.10 N, how long
will it take to empty the syringe? Now you can no longer ignore the viscosity
to the water, which is = 0.0010 Pas.