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The concepts of work and energy are linked to each other because an applied force can do work on an item and create a change in its energy. In general terms, we can say that work and energy are easily distinguishable. However, in Physics, these two terms are not as simple as they appear. It's a wide idea from which many different interpretations can be drawn.
- Work and energy have significant distinctions.
- Work is defined as the transmission of energy over a specific distance in a specific direction with the aid of a force.
- Energy is also known as the force that acts over a long distance.
- Both of them are referred to as scalar units. Work requires force and movement from one location to another.
| Table of Content |
Key Terms: Energy, Force, Work, Distance, displacement, Joule, Light energy, Sound energy, Heat energy, Kinetic Energy, SI units, Scalars and Vectors.
Definition of Work
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Work is a term that describes the energy transfer that occurs when an object is moved by an external force. Furthermore, for it to be deemed work, it must travel a distance in a certain direction with the help of the applied force. It means that the concept of work is predicated on the concept of displacement.
- Work is defined as the transmission of an energy amount via a force across a distance in the direction of the force in physics.
- Gaspard Coriolis was the first to create the term "work."
- He is a mathematician from France. In 1826, he created the term.
The following are some examples of work in real life:
- A person travels uphill in his or her car.
- You lift an object off the ground against the force of gravity, which is pulling the object down.
- However, It's worth noting that each of these examples demonstrates the presence of an external force that assists an object is moving in a specified direction.
- If you're wondering how work and energy are connected, you should realise that work is a mechanical representation of energy.
Furthermore, work calculation is a simple method that you should find simple to grasp. If you apply a force of f (in Newtons or N) to an object with a displacement of d (in metres or m), then work will be-
| W = Fd |
- The joule (or J) is the SI unit of work, and it is equivalent to a Newton meter (or N-m).
- Work, on the other hand, is measured in kg m2 s-2.
- The dyne-centimetre, or dyn-cm, is the CGS unit of work.
- You can alternatively write it in g cm2 s-2, which is its base unit.
Another intriguing application of work is that if you apply a force but there is no displacement, the work is null. To displace a wall, for example, you use the most force possible. In this instance, no work is being done because the wall does not change position even when force is applied.
Take notice of the definition of energy in order to comprehend the differences and relationships between work and energy.
Read Also: Thermal Properties of Matter
Definition of Energy
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The capacity of a thing to accomplish work is referred to as energy.
- Energy, in this context, refers to a physical system's ability to perform work.
- It comes in a variety of forms, unlike employment.
- This is an important aspect to remember while attempting to understand the distinction between work and energy.
The primary elements of these forms are light, sound, and heat. Kinetic, mechanical, potential, and electrical energy, on the other hand, are all types of energy. Consider the following energy examples:
- During a thunderstorm, light energy allows you to see the lightning and sound energy allows you to hear it.
- An incandescent bulb produces both light and heat energy when it is turned on.
Read more: Cyclic Process
SI Unit of Energy and Work
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The SI unit of Energy is the joule (J) and in the CGS system, its unit is erg.
- One joule equals the work done when a force of 1 N shifts a body by 1 metre.
- As a result, 1 J = 1 N-m.
- However, because both force and displacement are vector values, energy is a scalar number.
- As a result, they'll have a scalar product.
The dimensions of work and energy are the same and it is given as [ML2T-2].
Difference between Work and Energy
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Potential, kinetic, or nuclear energy, solar energy, or electrical energy are all examples of different types of energy. When an object is in motion, it is kinetic, and when it is at rest, it is potential. There is just one type of work, on the other hand. Both of these values are expressed in joules.
The differences between work and energy are given below:
| Work | Energy |
|---|---|
| The object was displaced as a result of the action. | It is defined as a system property or the ability to perform work. |
| Work equals force multiplied by distance. | Depending on the type of energy, several equations exist. |
| If the applied force is in the same direction as the displacement, the work is positive. If the applied force is in the opposite direction of the displacement, the work is negative. | Because this is a scalar quantity, there is no direction component. |
| Work is a form of energy exchange. | What is being conveyed is energy. |
| The force components are parallel to the displacement. | The work that is done produces energy. |
| Work is a scalar quantity | Energy is also a scalar quantity |
Physicists utilise work and energy to calculate and derive other quantities. This can be utilised in research labs for individuals to use in large-scale studies such as sports science.
Difference between Work and Energy
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| Related Articles | ||
|---|---|---|
| Calorimetry | Blackbody Radiation | |
| Thermal Conductivity | Coefficient of Linear Equation | |
| Thermal Expansion | Specific Heat Capacity | |
| Leatent Heat | Heat Capacity | |
Things to Remember
- The ability to produce or create work is referred to as energy. Work, on the other hand, is the ability to apply force to an object as well as a change in distance.
- There are many different kinds of energy, such as solar energy, but only one sort of work.
- Work was first used in 1826, although energy has been around since 4 BC.
- Work and energy are both scalar quantities.
- Joule is a unit of measurement for both work and energy.
Sample Questions
Ques: What is the International System of Measurement (SI) unit for Work and Energy? (2 Marks)
Ans: The joule is the SI unit of work and energy (J).
Ques: Make a list of the different types of energy stored in your body. (2 Marks)
(a) a watch spring
(b) water in motion
(c) stone rolling
(d) a hammer that has been raised
(e) an athlete who runs
Ans: (a) Potential Energy
(b) Kinetic Energy
(c) Kinetic Energy
(d) Potential Energy
(e) Kinetic Energy
Ques: Describe the energy shift that occurs when- (2 Marks)
→ Green plants make their own food.
→ When a nail is hammered hard, the head becomes heated.
Ans: → The sun's energy is converted into chemical energy.
→ The hammer's kinetic energy is converted into thermal energy.
Ques: A mass m body moves in a circular direction with a radius r. How much time is spent working on the body? (2 Marks)
Ans: Zero. This is due to the fact that the centripetal force exerted on the body is perpendicular to the body's displacement.
Ques: What conditions must be met in order for work to be considered positive? (2 Marks)
Ans: The angle between force and displacement should be sharp for positive work.
Ques: At 50 metres, a cyclist skids to a halt. The road exerts a force of 1000 N on the cycle during this operation, which is directed in the opposite direction of the motion. How much of the cycle's effort is done by the road? (2 Marks)
Ans: Displacement is given, and s = 50 m.
F = − 1000 N force
As, W = F x s
⇒ W = -1000 x 50J
So, W = 50000J Workdone
Ques: Establish a link between the SI unit of energy and the commercial unit of energy. (2 Marks)
Ans: The joule is the SI unit of energy, and the joule is the commercial unit of energy.
1000 W x 3600 s = 3.6 × 106J = 1 kWh
Ques: Calculate the work done in raising a 7 kg body vertically upwards to a height of 10 m. (2 Marks)
Ans: Given that m = 7 kg and s = 10m,
As W = F x s and E = mg x s,
So, Workdone will be w = 7 x 10 x 10 J = 700 J (Ans.)
Ques: A horse weighing 200 kilogrammes and a dog weighing 20 kilogrammes are both running at the same speed. Which of the two has the greater amount of kinetic energy? How? (2 Marks)
Ans: Because kinetic energy is exactly related to mass, the horse's kinetic energy is higher.
Ques: A boy uses a force of 40 N to push a book. As the book is shifted 25 cm along the course, determine the work done by this force. (2 Marks)
Ans: Force (F) = 40 N is the given value.
25 cm = 25 x 10-2 m which is displacement (s)
As, W = F x s = 40 x 25 x 10-2
So, W = 10J (Ans.)
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