A rod of length 50   c m is pivoted at one end. It is raised such that it makes an angle of 30 o from…

A rod of length 50 cm is pivoted at one end. It is raised such that it makes an angle of 30o from the horizontal as shown and released from rest. Its angular speed when it passes through the horizontal (in rad s-1 ) will be g=10 ms-2

  1. 203
  2. 30
  3. 302
  4. 302

Solution

From conservation of mechanical energy


Loss in gravitational PE= gain in KE

mgl2sin30o=12Iω2

mgl2sin30o=12ml23ω2

ω=3g2l=3×102×50×10-2=30 rad/s

Asked in: JEE Main 2019 (09 Jan Shift 2)

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