Angular momentum H per elemental fluid mass dm around some point is equal to the cross product r x u, where r is a position vector from that point to the elemental mass of fluid and u is the velocity of that fluid element. Use Reynolds Transport Theorem to write an integral form of the angular momentum balance:. a) Write the integrals representing the partial derivative of the angular momentum in a control volume w. r.t time and the flux of the angular momentum through the control surface. b) The total time derivative of the angular momentum obtained in part (a) is equal to the sum of the moments of all forces about the same point, (r x F).