Pilot Richard is studying momentum theory of propeller action. He wants to better understand why she moves as function of propellers forces. Richard pointed out the following notes about propeller’s momentum theory:

I) The momentum theory is used to describe the action of an “ideal” propeller. The propeller it self is assumed to be a “disc”.

II) The propeller causes uniform increase in pressure as the fluid passes through the disc coupled with uniform increase in fluid velocity.

III) The exact nature of the propeller (pitch, number of blades, shaft rpm, etc) is not important.

IV) There is an unlimited inflow of water to the propeller and the flow is not frictionless.

From theory of “Principles of Naval Architecture”, mark the correct alternative: