A system of particles is defined by many functions present in the system. Some of these functions are force, displacement, work, energy, etc.
One function can often be derived in terms of or from another function defined for the system. The functions are correlated such that it is often hard to differentiate them.
Work and energy are two such scalar functions that are dependent on one another and yet are different from one another.
It is important to know the difference between them to define a system completely and accurately.
Work vs Energy
The difference between Work and Energy is that work done is dependent on the displacement and direction of the object under observation, whereas the energy of the object is not dependent on displacement or direction of the object.
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 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 energy, potential energy, mechanical energy.
|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.||Derived from the Greek word ‘Energia’ and has been in use 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||If the object does not undergo any displacement, then the work done by the object is considered to be zero even if the object has covered a certain distance but came back 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 energy applied to be zero.|
|Equation||The equation for the numeric value of work is, Work=force x distance.||There are many equations for finding energy since there are many types of energy like electrical energy, chemical energy, etc.|
What is Work?
Work done is defined as the force applied on an object to cause displacement and a change in direction of the object’s motion.
It is essentially 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 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 on 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 the capacity of an object to undergo work done on producing 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 kind 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,
the SI unit for energy is also J and can also be represented in the form of N-m(Newton-metre).
Main Differences Between Work and Energy
- The two terms of‘ 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 work is done. Energy, on the other hand, is defined as the ability to produce or create work on an object. It is the ability of an object to undergo work.
- The origin of the two words is also different. The term ‘energy’ was derived by Aristotle in 4BC. It was coined from the Greek word ‘Energia’ and has been in use ever since the term was coined. Though work and energy are closely knit terms, the derivation of work was done much later. It was first coined by the French mathematician Gaspard-Gustave Coriolis in 1826.
- Energy and work are scalar quantity 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 direction of displacement of the object, then 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, 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.
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