What about potential energy in the Work Kinetic Energy Theorem?

AI Thread Summary
The discussion addresses the apparent contradiction in the Work-Kinetic Energy Theorem when lifting a block, as the initial and final kinetic energy are both zero, suggesting no work is done. However, lifting the block increases its potential energy, which is not accounted for in the kinetic energy equation. The total work done includes both the work you perform and the work done by gravity, resulting in a net work of zero. The work done against gravity is positive (mgh), while gravity does negative work (-mgh), balancing the equation. Thus, potential energy is a critical component that complements the kinetic energy perspective in this theorem.
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W_{total} = \delta K

What about lifting a block upward? If you lift a 10kg block vertically and bring it to a rest, you are doing work on it but the velocity in the beg and the end is 0, thus the equation says the work done on it is 0. But isn't there potential energy? Does the equation not look at potential energy?
 
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It is the total work - yours and that of gravity - which adds up to zero. The change of the potential energy is the negative of the work done by the force of gravity, You did mgh work, the gravity did -mgh work, they add up zero if the KE(initial)=KE(final).
 

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