What about potential energy in the Work Kinetic Energy Theorem?

In summary, the equation Wtotal = ∆K takes into account both the work done by lifting a block upward and the work done by gravity, resulting in a total of zero if the initial and final kinetic energies are equal. The equation does not directly consider potential energy, but it can be calculated as the negative of the work done by the force of gravity.
  • #1
toesockshoe
265
2
[itex] W_{total} = \delta K [/itex]

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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  • #2
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).
 

Related to What about potential energy in the Work Kinetic Energy Theorem?

1. What is the Work-Kinetic Energy Theorem?

The Work-Kinetic Energy Theorem states that the work done on an object is equal to the change in its kinetic energy. In other words, the net work done on an object is equal to the change in its speed.

2. How is the Work-Kinetic Energy Theorem different from the Work-Energy Principle?

While both concepts involve the relationship between work and energy, the Work-Kinetic Energy Theorem only considers the change in kinetic energy, while the Work-Energy Principle takes into account the changes in all forms of energy, including potential and thermal energy.

3. What is the formula for calculating work in the Work-Kinetic Energy Theorem?

The formula for work in the Work-Kinetic Energy Theorem is W = ΔKE = (1/2)mv2 - (1/2)mv02, where W is work, ΔKE is the change in kinetic energy, m is the mass of the object, v is its final velocity, and v0 is its initial velocity.

4. Can the Work-Kinetic Energy Theorem be applied to all types of motion?

Yes, the Work-Kinetic Energy Theorem can be applied to all types of motion, including linear, rotational, and oscillatory motion. It is a fundamental principle in classical mechanics.

5. How is the Work-Kinetic Energy Theorem used in real-life applications?

The Work-Kinetic Energy Theorem is used in various real-life applications, such as calculating the efficiency of machines and understanding the motion of objects in sports, such as a baseball being hit by a bat. It also plays a crucial role in fields like engineering, physics, and astronomy.

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