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JEE Main 2024 (9 Apr, Shift 1) · Rotational Kinetic Energy, Work & Power

Rotational Kinetic Energy, Work & Power question from JEE Main 2024 (9 Apr, Shift 1)

Q24JEE Main 2024 · 9 APR · SHIFT 1Medium

Rotational Kinetic Energy, Work & Power

A string is wrapped around the rim of a wheel of moment of inertia 0.40 kg m20.40\text{ kg m}^{2} and radius 10 cm10\text{ cm}. The wheel is free to rotate about its axis. Initially the wheel is at rest. The string is now pulled by a force of 40 N40\text{ N}. The angular velocity of the wheel after 10 s10\text{ s} is x rad/sx\text{ rad/s}, where xx is __________.

Numerical answer type. Work it out, then open the answer.

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Answer: 100

  1. Torque τ=FR=40×0.1=4\tau = FR = 40 \times 0.1 = 4 N m
  2. α=τI=40.40=10\alpha = \frac{\tau}{I} = \frac{4}{0.40} = 10 rad/s2^2
  3. From rest: ω=αt=10×10=100\omega = \alpha t = 10 \times 10 = 100 rad/s
  4. So x=100x = 100 rad/s.
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