Confusion about the Work-Energy Theorem

In summary, The conversation discusses the equation W = ΔE and its relation to work and energy. It also addresses why some textbooks may omit the potential energy factor in the equation. This is likely due to the section's focus on kinetic energy or the assumption of constant potential energy.
  • #1
AznBoi
471
0
Is this expression always true?: [tex]W=\Delta E[/tex] Please explain why this is using mathematical computations. I understand it conceptually but I just can't connect the two mathematically.

Also, why does my book only have the expression: [tex] W= \Delta KE[/tex] rather than: [tex] W= \Delta KE + \Delta PE[/tex] why did they leave the Potential energy out of the expression?
 
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  • #2
The equation [tex]W = \Delta E[/tex]
is simply saying that work done on or by a system causes a change in energy of that system.

As for your textbook, it's hard to say why it left out the potential energy factor, but most likely it is because it has not yet discussed potential energy in that specific section or the potential energy is always assumed to be constant for that particular section.
 
  • #3
Work is Delta KE

You can look at work as potential.
 

FAQ: Confusion about the Work-Energy Theorem

What is the Work-Energy Theorem?

The Work-Energy Theorem states that the work done on an object is equal to the change in its kinetic energy. In other words, the amount of work done on an object will result in a change in its velocity.

How is the Work-Energy Theorem derived?

The Work-Energy Theorem is derived from the principles of Newton's laws of motion. It can be mathematically proven by using the equation W = Fd, where W is work, F is force, and d is distance. This equation shows that the amount of work done on an object is directly proportional to the force applied and the distance over which the force is applied.

Can the Work-Energy Theorem be applied to all types of energy?

Yes, the Work-Energy Theorem can be applied to all types of energy, including kinetic energy, potential energy, and thermal energy. The theorem states that the total work done on an object will result in a change in its total energy.

What are some real-life applications of the Work-Energy Theorem?

The Work-Energy Theorem has many real-life applications, such as calculating the amount of work needed to lift an object, determining the speed of an object after it has been launched, and calculating the energy needed to overcome friction in a moving system.

Are there any limitations to the Work-Energy Theorem?

While the Work-Energy Theorem is a fundamental principle in physics and is applicable in many situations, it does have some limitations. It assumes that all external forces are conservative, meaning they do not dissipate energy. It also does not take into account factors such as air resistance and friction, which can affect the accuracy of its calculations.

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