A system of particles is defined by many functions present in the system. These functions are force, displacement, work, energy, etc.
One function can be derived from or from another function defined for the system. The functions are correlated such that it is hard to differentiate them.
Work and energy are two such scalar functions that are dependent on one another yet differ from one another.
Knowing the difference between them is important to define a system completely and accurately.
Key Takeaways
- Work is the amount of Energy transferred when a force is applied to an object and moves it in the direction of the force, while Energy is the ability to do work.
- Work is a scalar quantity as it depends on the object’s displacement, while Energy is a scalar or vector quantity depending on the type of Energy being considered.
- The unit of Work is Joule, and Energy is also Joule but can be expressed in other units like calorie or electron-volt.
Work vs Energy
In Physics, work is a measure of the force applied over a distance, signifying the effort to cause a movement. In Physics, energy is the overall capacity to do work or initiate change, and it can exist in several forms, such as kinetic, potential, thermal, nuclear, and more.
Work done on an object is the force applied on an object that causes a change in direction and displacement of the object. Work done on an object can be positive or negative depending on the relationship between the direction of force and the direction of displacement.
Energy is the ability of an object to undergo work. They produce or create work in a system with an object. The energy of an object is not dependent on the direction or the displacement of the object. There are many types of energy, like chemical, potential, and mechanical energy.
Comparison Table
| Parameters of Comparison | Work | Energy |
|---|---|---|
| Meaning | It is the force applied on an object to cause a change in direction or cause displacement of the object. | It is the ability to produce or create work. It is a function of a system. |
| Etymology | It has been in use since 1826. It was coined by the French mathematician Gaspard-Gustave Coriolis. | It is derived from the Greek word ‘Energia’ and has been used since Aristotle introduced this term in 4BC. |
| Direction | Work is direction-dependent. If the applied force is in the same direction as the direction of displacement, then work is positive and vice versa. | Energy is not dependent on the direction since it is a scalar quantity. |
| Displacement | Suppose the object does not undergo any displacement. In that case, the object’s work is considered zero, even if the object has covered a certain distance but returns to the initial position. | Energy is not entirely dependent on the value of displacement. So even if displacement is zero, it is not necessary for the energy applied to be zero. |
| Equation | The equation for the numeric value of work is workforce x distance. | There are many equations for finding energy since there are many types of energy like electrical, chemical, etc. |
What is Work?
Work done is the force applied to an object to cause displacement and a change in the direction of the object’s motion.
It is also used to measure the energy transferred to an object by the external force to cause a change in the state of the object.
Work done on an object is dependent on the direction. If the direction of force applied is the same as the direction of displacement caused, then the work done is positive.
If the direction of force applied is opposite, then the work done is negative.
The equation of work done is
work=force x displacement.
The SI unit of work done is Joules(J), but one can also use N-m. One joule is defined as 1 N of external force applied to cause a displacement of 1m.
Example: pushing a wall. In this case, the work done is zero because there is no displacement. Pushing a carton from A to B. There is work done.
What is Energy?
Energy is an object’s capacity to undergo work to produce an external force on the object. The energy of a system of particles is always conserved. So, it follows the law of conservation of energy.
For a system of particles, energy cannot be created nor destroyed. It has to change from one form to another. Therefore, there are many types of energy.
Examples: mechanical energy, chemical energy and potential energy.
Each kind of energy is used to define the energy used in different kinds of systems. Example: Chemical energy is the energy obtained from chemical changes in the surroundings.
Each type of energy has different energy equations.
The equation for potential energy is,
E=mgh
the SI unit for energy is also J and can be represented as N-m(Newton-metre).
Main Differences Between Work and Energy
- The two terms ‘ work’ and ‘energy’ have different definitions. Work is defined as the force applied to an object. The force applied should cause a change in direction or displacement of the object; only then is work done. On the other hand, energy is the ability to produce or create work on an object. An object can undergo work.
- The origin of the two words is also different. The term ‘energy’ was derived by Aristotle in 4 BC. It was coined from the Greek word ‘Energia’ and has been used since the term was coined. Though work and energy are closely knit, the work derivation was done much later. It was first coined by the French mathematician Gaspard-Gustave Coriolis in 1826.
- Energy and work are scalar quantities, i.e., the magnitude is not dependent on the direction. But, work done is dependent on direction. If the applied force is in the same direction as the object’s displacement direction, then the work done is positive and vice versa. Here, the magnitude of work done is not dependent on direction, but the work is done. Energy is not dependent on direction.
- For work done on an object, the object must undergo displacement. When the object moves a certain distance and returns to its initial position, though the distance is not zero, the displacement of the object is zero. In this case, the work done is also zero. Energy is not entirely dependent on the displacement of the object.
- The equation for calculating the magnitude of work is,
Work=force x displacement.
The equation for energy differs with different types of energy. For potential energy, the equation is E=mgh, whereas, for kinetic energy, the equation is E=1/2 kv^2.
- https://aapt.scitation.org/doi/abs/10.1119/1.1286662
- https://www.cabdirect.org/cabdirect/abstract/19681402006
Last Updated : 11 June, 2023
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Piyush Yadav has spent the past 25 years working as a physicist in the local community. He is a physicist passionate about making science more accessible to our readers. He holds a BSc in Natural Sciences and Post Graduate Diploma in Environmental Science. You can read more about him on his bio page.
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