Angular momentum is a physical quantity that describes the rotational motion of an object. It is a vector quantity, meaning it has both magnitude and direction. It is a conserved quantity, meaning it remains constant unless acted upon by an external torque.
Angular momentum is calculated by multiplying the moment of inertia, or the object's resistance to rotational motion, by the angular velocity, or the rate of change of the angular displacement. The formula for angular momentum is L = I x ω, where L is angular momentum, I is moment of inertia, and ω is angular velocity.
The units of angular momentum are kilogram meters squared per second (kg*m^2/s) in the SI system. In other systems, it can be expressed in terms of grams, centimeters, and seconds.
Angular momentum is conserved because of Newton's third law of motion, which states that for every action, there is an equal and opposite reaction. In rotational motion, this means that for every torque applied to an object, there is an equal and opposite torque acting on another object, keeping the total angular momentum of the system constant.
Some examples of angular momentum in everyday life include the spinning of a top, the rotation of the Earth around its axis, and the motion of a figure skater performing a spin. It is also responsible for the stability of objects like bicycles and gyroscopes.