in an electric motor, at the moment that half turn of the rotor (central electromagnet )the field of the electromagnet will stop turn off increase or flips

Two steel balls, each of mass m, are welded to a light rod of length l and negligible mass and are initially at rest on a smooth horizontal surface. a horizontal force of magnitude f is suddenly applied to the rod as shown. determine (a) the instantaneous acceleration a of the mass center g and (b) the corresponding rate at which the angular velocity of the assembly about g is changing with time.

See the attachment and solve question 5th

What is the role of the water cycle in maintaining freshwater levels in lake and rivers?