Q101 / 180 · NEET 2015 (Phase 2) · Physics

Point masses m1 and m2 are placed at the opposite ends of rigid rod of length L , and negligible mass. The rod is to be set rotating about an axis perpendicular to it. The position of point L on this rod through which the axis should pass so that the work required to set the rod rotating with angular velocity ω0 is minimum, is given by:
Figure

  • A
    x=m1m2L
  • B
    x=m2m1L
  • Correct answer
    C
    x=m2Lm1+m2
  • D
    x=m1Lm!+m2

Solution

K.E.=12I ω2

I is min. about the centre of mass

So, m1x=m2L-x

x=m2Lm1+m2

Hence, the correct answer is option: 'C'.

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