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6. system of particles and rotational motion — Physics STD 11 Science — Question

Rajasthan BoardEnglish MediumSTD 11 SciencePhysics6. system of particles and rotational motion1 Mark
MCQ
A body rotating at $20\ rad/sec$ is acted upon by a constant torque providing it a deceleration of $2\ rad/sec^2$. At what time will the body have kinetic energy same as the initial value if the torque continues to act ...... $\sec.$
  • ✓
    $20$
  • B
    $40$
  • C
    $5$
  • D
    $10$
✓

Answer

Correct option: A.
$20$
a
$\omega=\omega_{0}-\alpha t$

$-20=20-2 t$

$\therefore t=20 s$

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