Question

A mass M is moving with a constant velocity along a line parallel to the x-axis. Its angular momentum with respect to origin or z-axis is

• A. zero
• B. remains constant
• C. goes on increasing
• D. goes on decreasing

Answer 1

The correct option is C goes on increasing

A particle of mass ‘m’ is moving with velocity v parallel to the x-axis. Hence, its linear momentum is p = mv.



Now, the angular momentum of the particle about origin (any point as such) is $\overrightarrow{L}=\overrightarrow{r}\times \overrightarrow{p}=(\overrightarrow{r}\times \overrightarrow{v})$
Here, r is the perpendicular distance of the point from the origin. This distance remains constant throughout and so does the velocity. So, we can say that angular momentum remains constant with time.