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प्रश्न
Choose the correct alternatives:
- For a general rotational motion, angular momentum L and angular velocity ω need not be parallel.
- For a rotational motion about a fixed axis, angular momentum L and angular velocity ω are always parallel.
- For a general translational motion , momentum p and velocity v are always parallel.
- For a general translational motion, acceleration a and velocity v are always parallel.
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उत्तर
a and c
Explanation:
- For a general rotational motion where the axis of rotation is not symmetric. Angular momentum Z and angular velocity 0) need not be parallel. The wobbly motion of a wheel rotating about an axis inclined at a small angle to the symmetry axis of the wheel represents a situation where angular momentum and angular velocity are not parallel.
- Fixed axis should pass through CM of the body, so it is not necessary for angular momentum Z and angular velocity ω are always parallel.
- As we know in a general translational motion linear momentum is given by, p = mv, hence, the direction of p is always along v.
- In projectile motion, v and a are not always parallel.
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⊗ represents a unit vector going into the page.
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