COMEDK · Physics · 8. Rotational Motion
A uniform circular disc of mass \(400 \mathrm{~g}\) and radius \(4.0 \mathrm{~cm}\) is rotated about one of its diameter at an angular speed of \(10 \mathrm{rot} / \mathrm{s}\). The kinetic energy of the disc is
- A \(3.2 \times 10^{-1} \mathrm{~J}\)
- B \(1.6 \times 10^{-3} \mathrm{~J}\)
- C \(3.2 \times 10^{-3} \mathrm{~J}\)
- D \(6.4 \times 10^{-4} \mathrm{~J}\)
Answer & Solution
Correct Answer
(A) \(3.2 \times 10^{-1} \mathrm{~J}\)
Step-by-step Solution
Detailed explanation
Given, mass of disc, \(M=400 \mathrm{~g}=0.4 \mathrm{~kg}\) Radius, \(R=4 \mathrm{~cm}=4 \times 10^{-2} \mathrm{~m}\) Angular speed, \(\omega=2 \pi \times 10\) \[ =20 \pi \mathrm{rad} / \mathrm{s} \] \(\therefore\) Moment of inertia of disc about its diameter…
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