Spinning the wheels: intro to angular momentum

In summary, the object has rotational inertia I and begins to rotate with a constant angular acceleration of magnitude alpha after being initially at rest. To find the magnitude of angular momentum L after time t, use the equation L = I(omega), where omega is the angular velocity. To find omega, use the equation L = r*momentum and F = m(alpha)(r) and think about it similarly to finding speed with acceleration and time in a linear velocity problem.
  • #1
jaded18
150
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An object has rotational inertia I. The object, initially at rest, begins to rotate with a constant angular acceleration of magnitude alpha. What is the magnitude of the angular momentum L of the object after time t?
___

So I know that I have to find angular velocity and use the equation
L=angular momentum= I(omega) ... so how do i find this omega in terms of alpha and t??

I know that torque = r*F and L = r*momentum ... and F=m(alpha)(r) ? ..
 
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  • #2
If it were a linear velocity problem, could you find the speed given acceleration and time? Use similar thinking.
 
  • #3
ah that's too easy .. thanks lots:)
 

FAQ: Spinning the wheels: intro to angular momentum

What is angular momentum?

Angular momentum is a property of a rotating object that measures its resistance to changes in its rotational motion. It is defined as the product of the object's moment of inertia and its angular velocity.

How is angular momentum different from linear momentum?

Angular momentum is a rotational equivalent of linear momentum. While linear momentum is a measure of an object's motion in a straight line, angular momentum is a measure of its rotational motion. Linear momentum is a vector quantity, while angular momentum is a pseudovector quantity.

What factors affect the angular momentum of an object?

The angular momentum of an object is affected by its moment of inertia, angular velocity, and the torque acting on it. Increasing any of these factors will increase the object's angular momentum, while decreasing them will decrease the angular momentum.

How is angular momentum conserved?

According to the law of conservation of angular momentum, the total angular momentum of a closed system remains constant. This means that if no external torques act on the system, the initial angular momentum will remain unchanged.

How is angular momentum used in real-life applications?

Angular momentum has many applications in various fields, such as physics, engineering, and astronomy. It is used in the design of rotating machinery, such as turbines and engines, to ensure their stability and efficiency. In astronomy, angular momentum is used to describe the motion of planets and other celestial objects.

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