How is a split-ring commutator used to switch the direction of the current?

A split-ring commutator is used to switch the direction of the current. A commutator is a split metal ring connected to conducting brushes that allow the electric current to pass into the ring. When the current produces a turning force of the motor, it causes the motor to rotate in a clockwise direction. This allows the current to be broken for a fraction of a second. However, momentum causes the wire to keep turning, which allows the current to switch direction. So the force on the left still acts upwards and the force on the right still acts downwards. Therefore the commutator allows the motor to keep turning in the same direction.