How does the viscous force of the liquid affect momentum in this problem?

[TeddyLu]

Homework Statement

Please see attached file for problem statement

Homework Equations

ΣM = M_in - M_out = 0

The Attempt at a Solution

I have tried using the equation of conservation of momentum on this problem but I'm getting stuck at how the viscous force of the liquid is playing a role in this problem. In addition, would I take in affect that the force of the liquid that is applied on the cone is applied throughout the whole area of the cone, therefore, meaning that I need to find the area of the surface of the cone that the liquid is acting upon?

 

[Simon Bridge]

You need to use calculus to do the change in momentum.

 

[Chestermiller]

Are you learning about macroscopic momentum balances in your course? In your relevant equation, does M stand for mass or for momentum?