Question About Work-Energy Theorem

This means that the sum of all individual works done by each force is equal to the change in kinetic energy of the object. In summary, the Work-Kinetic Energy Theorem states that the net work done on an object is equal to the change in its kinetic energy, which can be expressed as W=ΔK. This applies even in cases where multiple forces are acting on the object, as long as the net work and net change in kinetic energy are considered.
  • #1
dlacombe13
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Very simple question. So I am on a homework problem, and I want to make sure that I am using this theorem correctly. My book states that the Work-Kinetic Energy Theorem is:

W=ΔK

Now the solution to this problem involved multiple forces and thus each force is doing work. So my question is, is it legal to say that:

∑W = ΔK
 
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  • #2
dlacombe13 said:
Very simple question. So I am on a homework problem, and I want to make sure that I am using this theorem correctly. My book states that the Work-Kinetic Energy Theorem is:

W=ΔK

Now the solution to this problem involved multiple forces and thus each force is doing work. So my question is, is it legal to say that:

∑W = ΔK

Yes. Precisely.
 
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Likes vanhees71 and dlacombe13
  • #3
Thank you, the problem makes complete sense to me now!
 
  • #4
In Newton's second law, F = ma, F is always the net force acting on an object. Therefore, in the work-energy theorem, W is always the net work done on the object.
 

1. 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 is directly proportional to the change in its speed or velocity.

2. How is the Work-Energy Theorem used in physics?

The Work-Energy Theorem is a fundamental principle used in physics to analyze the motion of objects and understand the transfer of energy. It is often used in conjunction with other laws and principles, such as Newton's laws of motion, to solve problems related to motion and energy.

3. Can you provide an example of the Work-Energy Theorem in action?

Imagine a car accelerating from a stop. The engine exerts a force on the car, causing it to move and gain speed. According to the Work-Energy Theorem, the work done by the engine is equal to the change in the car's kinetic energy. In this case, the work done by the engine increases the car's kinetic energy, resulting in an increase in its speed.

4. What are the units of measurement for work and energy in the Work-Energy Theorem?

The SI units for both work and energy are joules (J). This means that both work and energy can be measured in terms of the amount of force applied and the distance over which it is applied. Other common units for energy include kilowatt-hours (kWh) and calories (cal).

5. Are there any limitations to the Work-Energy Theorem?

The Work-Energy Theorem is based on the assumption that there are no external forces acting on the object, other than the force being applied to it. In real-world situations, there may be other factors at play, such as air resistance or friction, which can affect the validity of the theorem. Additionally, the Work-Energy Theorem only applies to objects moving in a straight line, and may not be applicable to objects moving in a curved path.

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