I know how to apply the linear momentum equation for the control volume, but I am not sure why the V2 (velocity of flow from section 2) is V*cos(60).
The only reason I can see is the velocity being constant. And since there are two outlet with equal area, the velocity is half? (1/2)V*cos(60) + (1/2)V*cos(60)= V*cos(60)
I just want to make sure my reasoning is right.