A constant torque of $200 \mathrm{~N}$ turns a flywheel, which is at rest, about an axis through its centre…

A constant torque of $200 \mathrm{~N}$ turns a flywheel, which is at rest, about an axis through its centre and perpendicular to its plane. If its moment of inertia is $50 \mathrm{~kg}-\mathrm{m}^{2}$, then in 4 second, what will be change in its angular momentum?
  1. $800 \mathrm{~kg}-\mathrm{m}^{2} / \mathrm{s}$
  2. $200 \mathrm{~kg}-\mathrm{m}^{2} / \mathrm{s}$
  3. $40 \mathrm{~kg}-\mathrm{m}^{2} / \mathrm{s}$
  4. $20 \mathrm{~kg}-\mathrm{m}^{2} / \mathrm{s}$

Solution

Change in angular momentum $=\tau . t$ $=200 \times 4=800 \mathrm{~kg} \mathrm{~m}^{2} / \mathrm{s}$ /

Asked in: MHT CET 2020 (19 Oct Shift 1)

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