A particle of mass 20   g is released with an initial velocity 5   m   s - 1 along the curve…

A particle of mass 20 g is released with an initial velocity 5 m s-1 along the curve from the point A, as shown in the figure. The point A is at height h from point B. The particle slides along the frictionless surface. When the particle reaches point B, its angular momentum about O will be: (Take g=10 m s-2)

  1. 3 kg m2 s-1
  2. 2 kg m2 s-1
  3. 6 kg m2 s-1
  4. 8 kg m2 s-1

Solution

Applying conservation of energy,

mgh=12mvB2-12mvA2
vB=2gh+vA2
vB=2×10×10+25
vB=15 m s-1
Angular momentum about O

LO=mvBh+a
LO=20×10-3×15×20 kg m2 s-1
LO=6 kg m2 s-1

Asked in: JEE Main 2019 (12 Jan Shift 2)

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