Work Energy And Power Question 246
Question: A uniform chain of length 2 m and mass 0.1 kg overhangs a smooth table with its two third part lying on the table. Find the kinetic energy of the chain as it completely slips- off the table.
Options:
A) $ \frac{8}{9}J $
B) $ \frac{12}{5}J $
C) $ \frac{3}{7}J $
D) $ \frac{11}{3}J $
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Answer:
Correct Answer: A
Solution:
[a] $ U_1 =\int\limits_0^{\ell /3}{-\frac{m}{\ell }gxdx=-\frac{1}{18}}mg\ell ; $
$ U_2 =\int\limits_0^{\ell }{-\frac{m}{\ell }gxdx=-\frac{1}{2}}mg\ell ; $
$ loss in P.E. = U_1- U_2 = \frac{4}{9} mg\ell $
$ =\frac{4}{9}\times 0.1\times 10\times 2=\frac{8}{9}J=FinalK.E. $
