The potential energy of a particle of mass m at a distance r from a fixed point O is given by V r = k r 2 /…

The potential energy of a particle of mass m at a distance r from a fixed point O is given by Vr=kr2/2, where k is a positive constant of appropriate dimensions. This particle is moving in a circular orbit of radius R about the point O. If v is the speed of the particle and L is the magnitude of its angular momentum about O, which of the following statements is (are) true?
  1. v=k2mR
  2. v=kmR
  3. L=mkR2
  4. L=mk2R2

Solution


\(\begin{aligned} & V=\frac{k r^2}{2} \\ & L=m v R \\ & =m \sqrt{\frac{k}{m}} R . R \\ & =\sqrt{m k} R^2 \\ & L=\sqrt{\frac{k}{m} R^2} \end{aligned}\)

Asked in: JEE Advanced 2018 (Paper 1)

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