Momentum is also an incorrect term here. The rudder is needed to counteract Thrust, which is a force, by producing an equal force in the opposite direction.
Force is certainly wrong.
What would you call the product of a force and its applicable lever arm?
Thrust has its lever arm from the relevant engine to airplane centreline. But what is the proper lever arm for the rudder aerodynamic force? Where is the pivot point - at main landing gear (in contact with runway and independent of CoG location) or the CoG location of the airplane (so that lever arm is shorter with rear CoG)?