Department of Pre-University Education, KarnatakaPUC Karnataka Science Class 11
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A Particle Moves on a Straight Line with a Uniform Velocity. Its Angular Momentum - Physics

Answer in Brief
Fill in the Blanks

A particle moves on a straight line with a uniform velocity. Its angular momentum __________ .

(a) is always zero

(b) is zero about a point on the straight line

(c) is not zero about a point away from the straight line

(d) about any given point remains constant.

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Solution

(b) is zero about a point on the straight line

(c) is not zero about a point away from the straight line

(d) about any given point remains constant

 

(b) Angular momentum = \[m\left( \overrightarrow{r} \times \overrightarrow{v} \right)\]

If the point is on the straight line, \[\overrightarrow{r} \text{ and }  \overrightarrow{v}\] will have the same direction and their cross product will be zero. Hence, angular momentum is zero.

(c) If the point is not on the straight line, \[\overrightarrow{r} \text{ and }  \overrightarrow{v}\] will not have the same direction and their cross product will not be zero. Hence, angular momentum is non-zero.

(d) No external torque is applied on the body; therefore, its angular momentum about any given point remains constant.

  Is there an error in this question or solution?
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APPEARS IN

HC Verma Class 11, 12 Concepts of Physics 1
Chapter 10 Rotational Mechanics
MCQ | Q 3 | Page 194
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