What about potential energy in the Work Kinetic Energy Theorem?

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SUMMARY

The Work Kinetic Energy Theorem states that the total work done on an object is equal to the change in kinetic energy (W_total = δK). When lifting a 10kg block vertically, work is performed against gravity, resulting in an increase in potential energy, despite the initial and final kinetic energy being zero. The work done by the lifter (mgh) and the work done by gravity (-mgh) cancel each other out, confirming that the total work is zero when kinetic energy remains unchanged.

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  • Basic knowledge of potential energy concepts
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  • Ability to perform calculations involving mass, height, and gravitational acceleration
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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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