Concept Items
6.1 Angle of Rotation and Angular Velocity
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1\,\text{rev} = \pi\,\text{rad}=180^\circ
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1\,\text{rev} = \pi\,\text{rad}=360^\circ\!
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1\,\text{rev} = 2\pi\,\text{rad} = 180^\circ\!
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1\,\text{rev} = 2\pi\,\text{rad}=360^\circ
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Tangential velocity is the average linear velocity of an object in a circular motion.
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Tangential velocity is the instantaneous linear velocity of an object undergoing rotational motion.
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Tangential velocity is the average angular velocity of an object in a circular motion.
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Tangential velocity is the instantaneous angular velocity of an object in a circular motion.
What kind of motion is called spin?
- Spin is rotational motion of an object about an axis parallel to the axis of the object.
- Spin is translational motion of an object about an axis parallel to the axis of the object.
- Spin is the rotational motion of an object about its center of mass.
- Spin is translational motion of an object about its own axis.
6.2 Uniform Circular Motion
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a_c = \frac{\omega^2\!}{r}
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a_c = \frac{\omega}{r}
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a_c = r\omega^2\!
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a_c = r\omega\!
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F_c = \frac{a_c^2\!}{m}
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F_c = \frac{a_c}{m}
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F_c = ma_c^2\!
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F_c = ma_c
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center-seeking
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center-avoiding
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central force
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central acceleration
6.3 Rotational Motion
Conventionally, for which direction of rotation of an object is angular acceleration considered positive?
- the positive x direction of the coordinate system
- the negative x direction of the coordinate system
- the counterclockwise direction
- the clockwise direction
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It opens slowly because the lever arm is shorter so the torque is large.
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It opens slowly because the lever arm is longer so the torque is large.
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It opens slowly because the lever arm is shorter so the torque is less.
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It opens slowly because the lever arm is longer so the torque is less.
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Angular acceleration is the rate of change of the displacement and is negative when \omega increases.
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Angular acceleration is the rate of change of the displacement and is negative when \omega decreases.
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Angular acceleration is the rate of change of angular velocity and is negative when \omega increases.
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Angular acceleration is the rate of change of angular velocity and is negative when \omega decreases.