A horizontal pipe carrying water tapers from 200mm diameter
at point A to 100mm diameter at point B. If the volume flow
rate is 55 litres/second find the pressure difference between
the points A and B neglecting any losses in the pipe.

Delta pressure = 45938[Pa]

Explanation:

This is a classic bernoulli equation problem, but first we must find the velocity at both ends of the pipe, knowing the diameters of each end.

Now we can calculate the two velocites VA and VB

Using the bernoulli equation we have:

Where ro = density of water = 1000[kg/m^3]

force is mass*acceleration.

we have a very small mass: 11.4*0.001 kg

if we want 0.035n of force, we need an acceleration:

0.035 = 11.4*0.001*a

a = 0.035/(11.4*0.001) m/s^2