A particle is released on a vertical smooth semicircular track from point X so that, O X makes angle θ…


A particle is released on a vertical smooth semicircular track from point X so that, OX makes angle θ  from the vertical (see figure). The normal reaction of the track on the particle vanishes at the point Y where OY makes an angle ϕ with the horizontal. Then
  1. sinϕ=23cosθ
  2. sinϕ=34cosθ
  3. sinϕ=12cosθ
  4. sinϕ=cosθ

Solution

mgRcosθ-Rsinϕ=12mV2  .......(1)

On losing contact N=0⇒mgsinϕ=mV2R  ......(2)



mgRcosθ-sinϕ=12mgRsinϕ

2cosθ=3sinϕ

Asked in: JEE Main 2014 (19 Apr Online)

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