Angular Momentum Change Formula |
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\( \Delta L \;=\; L_f - L_i \) (Angular Momentum Change) \( L_f \;=\; \Delta L + L_i \) \( L_i \;=\; L_f - \Delta L \) |
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| Symbol | English | Metric |
| \( \Delta L \) = Angular Momentum Change | \(ft-lbf-sec\) | \(kg-m^2 \;/\; s\) |
| \( L_f \) = Final Angular Momentum | \(ft-lbf-sec\) | \(kg-m^2 \;/\; s\) |
| \( L_i \) = Initial Angular Momentum | \(ft-lbf-sec\) | \(kg-m^2 \;/\; s\) |
Angular momentum change, abbreviated as \(\Delta L\), is the difference in an object’s angular momentum between two states of motion and describes how the rotational motion of a system evolves over time. Angular momentum depends on the object’s moment of inertia and its angular velocity, so a change can occur if the object speeds up or slows down its rotation, redistributes its mass relative to the axis of rotation, or both. According to rotational dynamics, a change in angular momentum is caused by the action of an external torque acting over a period of time, analogous to how a force causes a change in linear momentum. In isolated systems with no external torque, angular momentum remains conserved, meaning there is no angular momentum change even if the system’s shape or rotational speed changes.
