A block of mass $m$ is at natural length initially.It is attached to two springs having spring constant $k1$ and $k2$. It is attached in such a way that when one elongates ,the other compresses.Using work energy theorem , I need to find the velocity of the block at half the amplitude of release of the block. Spring stores energy as $0.5kx^2$. The sign is decided if the force by spring is opposing displacement($-ve$) or along displacement($+ve$). Is this concept also applied in Work-energy equation where initial system energy is equal to final energy system?
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$\begingroup$ Energy is a scalar quantity. It has no sign $\endgroup$– Bob DApr 21, 2020 at 7:47
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$\begingroup$ So does it mean we take the mod of energy in each object in system for initial and final energy in Work-Energy conservation equation? $\endgroup$– LGEYHApr 21, 2020 at 7:49
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$\begingroup$ The change in kinetic energy can be positive or negative but the value of kinetic energy has no sign $\endgroup$– Bob DApr 21, 2020 at 7:55
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$\begingroup$ Kinetic energy depends on v squared. It is always positive. Spring energy is similar. $\endgroup$– R.W. BirdApr 21, 2020 at 16:07
1 Answer
The change in kinetic energy of a system has sign.
Whereas change in potential energy of a system solely depends on reference.