Angular momentum
Definition
Angular momentum refers to the rotational equivalent of linear momentum. It describes how fast an object rotates around an axis and depends on its mass distribution and rotational speed.
Analogy
Think of figure skaters spinning on ice. When they pull their arms closer to their body, they spin faster due to conservation of angular momentum. This can be compared to pulling in your arms while sitting on a rotating office chair - you will start spinning faster!
Related terms
Torque: Torque is the measure of how much force causes an object to rotate around an axis. It determines how quickly angular momentum changes.
Moment of inertia: Moment of inertia quantifies an object's resistance to changes in its rotation rate. Objects with larger moments of inertia require more torque to change their rotation.
Conservation of angular momentum: This principle states that if no external torques act on a system, then the total angular momentum remains constant.
"Angular momentum" appears in:
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Practice Questions (6)
A child of mass M is sitting on a circular platform of mass 5M which is rotating counterclockwise without friction. Which of the following actions could the child do to increase the angular momentum of the child-platform system?
A rotating object with a radius of 0.75m experiences a constant force of 15N applied tangentially at its edge for a span of 10 seconds. What is the object's change in angular momentum?
What is the change in angular momentum of a metal rod initially at rest that experiences a net torque of 24 N*m over a span of 10 seconds?
A constant force of 8N is applied tangentially to a disk with a diameter of 100 cm for 10 seconds. What is the change in angular momentum after 10 seconds?
Express the change in angular momentum to a wrench of length L that experiences a clockwise tangential force F a distance of L away from the center of rotation and a counterclockwise tangential force of 2F a distance of L/2 away from the center of rotation over a span of 5 seconds?
If angular momentum is graphed on the y axis and angular velocity is graphed on the x axis, what can be used to find the moment of inertia?
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