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Two equal masses are attached to the two ends of a spring of spring constant k. The masses are pulled out symmetrically to stretch the spring by a length x over its natural length. The work done by the spring on each mass is(a) 1/2 kx2 (b)-1/2 kx2 (c) 1/4 kx2 (d)-1/4 kx2 |
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Answer» (d) -1/4kx2. Explanation:- The work done by the spring on both of the masses is equal to the potential energy stored in the spring. The potential energy stored in the spring = -½kx². Since the masses are pulled out symmetrically, the work done by the string on each mass =½(-½kx²) =-¼kx². The negative sign is for the fact that displacement is opposite to the force. |
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