WBJEE · Physics · Work Power Energy
A uniform rope of length \(4 \mathrm{~m}\) and mass \(0.4 \mathrm{~kg}\) is held on a frictionless table in such a way that \(0.6 \mathrm{~m}\) of the rope is hanging over the edge. The work done to pull the hanging part of the rope on the to the table is, (Assume \(\mathrm{g}=10 \mathrm{~m} / \mathrm{s}^2\) )
- A \(0.36 \mathrm{~J}\)
- B \(0.24 \mathrm{~J}\)
- C \(0.12 \mathrm{~J}\)
- D \(0.18 \mathrm{~J}\)
Answer & Solution
Correct Answer
(D) \(0.18 \mathrm{~J}\)
Step-by-step Solution
Detailed explanation
\(\begin{aligned} & \text {Hint : } W=\frac{\mathrm{mgL}}{2}=\frac{0.4}{4} \times 0.6 \times 10 \times \frac{0.6}{2} \\ & =0.1 \times 0.6 \times 10 \times 0.3 \\ & =0.18 \mathrm{~J} \end{aligned}\)
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