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NEET · Physics · STD 11 - 6. system of particles and rotational motion
A disc of radius \(2\; \mathrm{m}\) and mass \(100\; \mathrm{kg}\) rolls on a horizontal floor. Its centre of mass has speed of \(20\; \mathrm{cm} / \mathrm{s} .\) How much work is needed to stop it?
- A \(3 \mathrm{J}\)
- B \(30\; \mathrm{kJ}\)
- C \(2 \;J\)
- D \(1\; \mathrm{J}\)
Answer & Solution
Correct Answer
(A) \(3 \mathrm{J}\)
Step-by-step Solution
Detailed explanation
\(\mathrm{W}_{\mathrm{all}}=\Delta \mathrm{KE}\) \(\Rightarrow W=0-\frac{1}{2} m v_{c m}^{2}\left(1+\frac{K^{2}}{R^{2}}\right)\)
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