State the Law of Conservation of Angular Momentum and Explain with a Suitable Example

Answer:

• A rotating object possesses angular momentum in it. The more the angular momentum in the object, the more it will want to rotate. For example, a spinning top possesses a large angular momentum. 
• In short, angular momentum is a measure of an object’s ability to keep spinning. 
• The law of conservation of angular momentum states that when there is no external torque present in the system, then its total angular momentum remains conserved. In other words, the total angular momentum of an isolated system remains constant both in magnitude and direction.
• If I1 is the moment of inertia when the angular velocity of the object is ω1 and I2 is the moment of inertia when the angular velocity of the object is ω2. Then by the law of conservation of angular momentum, 

                                I1 ω1 = I2 ω2

• A diver jumping into the pool of water depicts the law of conservation of angular momentum. When the diver jumps in the air, he folds his hands and legs inwards so that his moment of inertia decreases. Consequently, his angular speed increases and he spins faster. When he is about to land in the pool, he opens his hands and legs, so his moment of inertia increases and speed decreases. Thus, he lands in the pool at a lesser speed.