Write an example for the motion in which an angular momentum remains constant.
Answers
Angular momentum is constant for a spinning object (say, a bowling ball) dropped on a surface where there is some friction. The ball will increase its linear speed until it stops slipping, but the angular momentum about some point on the surface remains unchanged. The angular momentum of the ball due to its rotation will decrease but will be offset by the increase in the angular momentum due to the increase in the linear momentum about the chosen point.
Answer:
An illustration of angular momentum conservation is an ice skater whirling.
Explanation:
Due to the minimal friction between the skates and the ice, the torque, or spinning effect of the force, is virtually equivalent to zero. With her arms outstretched, an ice skater is spinning on the tip of her skate. Because of the negligibly small net torque on her, her angular momentum is conserved. The skater pulls his arms in tightly, dramatically increasing her rate of spin and lowering his moment of inertia. The rotational equivalent of linear momentum in physics is called angular momentum, also known as moment of momentum or rotational momentum. The fact that the total angular momentum of a closed system remains constant makes it a crucial number in physics.
Thus, when no external torques are acting on the system, angular momentum is preserved.