Conservation of Angular Momentum and its Applications #8211; The law of conservation of angular momentum states that, if there is no external torque acting on the body. Then the total angular momentum will remain unchanged. If τ = dL/dt = 0 ⇒ L<sub>initial</sub> = L<sub>final</sub> In other form we can also write, L = Iω = constant. Applications (i) this explains why an ice skater brings his arms and legs close to the verticle axis of rotation to increase his angular speed (ω). (ii) This principle is also used by gymnastics, swimmers, acrobats and ballet dancers etc.