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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 wheel is rotating about an axis through its centre at $720$ revolutions per minute. It is acted on by constant torque opposing its motion for $8\ seconds$ till it comes to rest. The number of revolutions made by the wheel in the $8\ seconds$ is 
  • ✓
    $48$
  • B
    $72$
  • C
    $96$
  • D
    $120$
✓

Answer

Correct option: A.
$48$
a
$\frac{\theta }{t} = \frac{{\omega  + {\omega _0}}}{2}$

$\theta  = \frac{{720}}{{2 \times 60}} \times 8 = 48$

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