NEET-XII-Physics
10: Rotational Mechanics
- #3A particle moves with a constant velocity parallel to the X-axis. Its angular momentum with respect to the origin
(a) is zero
(b) remains constant
(c) goes on increasing
(d) goes on decreasing.digAnsr: bAns : (b) remains constant
For angular momentum, we have:
`` \stackrel{\to }{L}=m\left(\stackrel{\to }{r}\times \stackrel{\to }{v}\right)``
`` \stackrel{\to }{v}=v\stackrel{‸}{i}\,\mathrm{\,and\,}\stackrel{\mathit{\to }}{r}=x\stackrel{\mathit{^}}{i}\mathit{+}y\stackrel{\mathit{^}}{j}``
`` \,\mathrm{\,So\,}\mathit{,}\stackrel{\mathit{\to }}{L}\mathit{=}\mathit{-}mvy\stackrel{\mathit{^}}{k}``
m, v and y are constant; therefore, angular momentum remains constant.
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