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| 183_notes:ang_momentum [2021/06/04 04:11] – [Translational Angular Momentum] stumptyl | 183_notes:ang_momentum [2021/06/04 04:12] (current) – [Rotational Angular Momentum] stumptyl |
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| ==== Rotational Angular Momentum ==== | ==== Rotational Angular Momentum ==== |
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| As you [[183_notes:rot_ke|read with rotational kinetic energy]], it is often useful to think about the motion of a system about its center. In those notes, you [[183_notes:rot_ke#atoms_in_rotating_objects_can_move_with_different_speeds|read about how the translational kinetic energy of atoms in a solid as the move around some central rotation axis]] can be described with rotational kinetic energy. Rotational angular momentum is a similar construct. It is not that a translating and rotating object has a separate kinds of angular momentum, but that you can mathematically separate the angular momentum due to translation and due to rotation to think about the two parts more easily. | As you [[183_notes:rot_ke|read with rotational kinetic energy]], it is often useful to think about the motion of a system about its center. In those notes, you [[183_notes:rot_ke#atoms_in_rotating_objects_can_move_with_different_speeds|read about how the translational kinetic energy of atoms in a solid as the move around some central rotation axis]] can be described with rotational kinetic energy. Rotational angular momentum is a similar construct. //It is not that a translating and rotating object has a separate kinds of angular momentum, but that you can mathematically separate the angular momentum due to translation and due to rotation to think about the two parts more easily.// |
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| Consider the spinning ball, person, stool system from the demonstration. In this case, the whole system rotates with the same angular velocity ($\omega$) after the ball was caught. An atom in the ball at a distance of $r_{\perp}$ from the rotation axis is therefore moving with a linear speed $v = r_{\perp}\omega$. Here, $r_{\perp}$ is the perpendicular distance from the rotation axis to the atom in the ball. | Consider the spinning ball, person, stool system from the demonstration. In this case, the whole system rotates with the same angular velocity ($\omega$) after the ball was caught. An atom in the ball at a distance of $r_{\perp}$ from the rotation axis is therefore moving with a linear speed $v = r_{\perp}\omega$. Here, $r_{\perp}$ is the perpendicular distance from the rotation axis to the atom in the ball. |