A) \[\rho L{{v}^{2}}/4\]
B) \[\rho L{{v}^{2}}/2\]
C) \[\rho L{{v}^{2}}/3\]
D) \[\rho L{{v}^{2}}\]
Correct Answer: B
Solution :
Initial speed of the coil is 0 m/s. Final speed = v (uncoiling speed) Mass of the coil \[=\rho L\] Thus, work done \[W=\Delta KE={{K}_{f}}-{{K}_{i}}\] \[=\frac{1}{2}\times (\rho L){{(v)}^{2}}-0=\frac{1}{2}\rho L{{v}^{2}}\]
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