Category: Physics Notes PPT

Even though joule (J) refers to the SI unit of both work and energy, specific fundamental differences separate one from the other. Consequently, you should know about the finer points of work and energy individually to get better clarity on the difference between work and energy. 

Here, take note of what work and energy are before moving on to their differences.

It cannot be considered an exaggeration of the obvious if one says that Work and Energy are one of the most important parts of Physics. Well, not only physics but also of our everyday life to be precise. And hence understanding these topics are very much important for the students. Also, the principles of Work and energy are applied in many other areas of science as well. But more often than not students may get a little confused between the work and energy, and hence having the difference between the both are important.

But for understanding this topic the students must have a good explanation of the topic because only having an explanation does not suffice the need of the students, because if the explanation is tough to comprehend then it can only make things worse for the students. Hence, a good explanation, that is to say, the explanation which is easy to understand for the students, is a must. And hence provides such a type of solution to the students, for the topic of the difference between Work and Energy.

What is Work? 

Work essentially measures the transfer of energy involved in moving an object by an external force. Moreover, it has to cover a distance in a specific direction with the help of the applied force for it to be considered work. It means the concept of work hinges on that of displacement. 

Some of the Real-Life Examples of Work Include The Following – 

Note that all these instances show the presence of an external force that helps an object move in a specific direction. Now if you are wondering how work and energy are related to each other, you should know that it acts as a mechanical manifestation of energy.

 

Besides, the calculation of work is an easy process that you should find convenient to grasp. Suppose, you apply a force ‘f’ (in Newton or N) on an object and it has a displacement of  ‘d’ (in meters or m), then work – 

w = Fd

The SI unit of work is the joule (or J) which is equal to Newton-meter or N-m. On the other hand, the base unit for work is kg m2 s-2. The CGS unit of work is dyne-centimeter or dyn-cm. You can also express it in its base unit which is g cm2 s-2. 

Another interesting implication of work that you should note is that even if you apply a force and the displacement is nil, the work becomes null. For example, you exert the maximum force on a wall to displace it. Since the wall does not change position even with the application of force, no work is being done in this situation. 

To understand the differences and relationship between work and energy, you will have to take note of the definition of energy. 

What is Energy? 

In Physics, energy deals with the capacity of an object to do work. More precisely, energy refers to the ability of a physical system to undergo work. Unlike work, it exists in several forms. This is a vital pointer that must be noted while trying to comprehend the difference between work and energy. 

These forms mainly include basics such as light, sound, and heat. On the other hand, energy also comprises kinetic, mechanical, potential, and electrical energy. Consider the following examples of energy – 

The SI unit of energy is the joule (J), where one joule equals the work when a force of 1 N shifts a body by 1 meter. Therefore, 1 J = 1 N-m. However, energy is a scalar quantity because both force and displacement are vector quantities. As a result, their product will be scalar. 

Since you know both work and energy definitions, you should go over the following differences between them. 

 

What is the Difference Between Work and Energy? 

Work and energy have the following differences – 

• Now that you are aware of the difference between work and energy, do go through similar topics to gain advanced knowledge on this subject. Also, you can download our app to access an enhanced learning experience.

Benefits of Having a Clear Understanding Between Work and Energy.

You may think, it is obvious that there the concepts of work and energy are different, and by understanding their meaning and definition you can easily understand the difference. So, yes, it is true that you can understand the difference between both the concepts, that is to say, work and energy, by going through their meaning and definition. But there are quite a few reasons why there should be a clear distinction between Work and Energy.

• Since work and energy are very closely related topics, it helps in clearing the confusion between the topic of Work and Energy. Otherwise, such confusion may make you use one for the other. That is to say, taking work for energy and vice versa.

An Overview of the Work.

When energy is transferred from an object, or to an object, by using the force, it is called Work, in physics. More often than not, work is represented as the product of displacement and force. In short, work is nothing but the transfer of energy, the energy is transferred in an object by the external force.

Take the cricket ball for an example, when the bowler throws the ball, he transfers the energy that he has produced to the ball. And hence the ball gets thrown. And the same thing happens when the batsman hits the ball.

An Overview of Energy.

The capacity of the object to work is regarded as the energy in physics. The energy from one object to the other. Also, there are various types of energy such as kinetic energy, Potential energy, heat energy, and electrical energy.

If you wish to learn more about energy then you may like to follow this link.

RTD and Thermocouple

RTD, which stands for Resistance Temperature Detectors, is the common type of sensor used for temperature measurements. Similar to RTD, Thermocouple is also widely used for measuring temperature range. These two sensor types are chosen over other methods for measurements due to their ease of use. Additionally, these avoid the tiresome conversion process while processing temperature measurements. However, there are some points of difference between RTD and Thermocouple, which are important to understand. This article highlights the important distinctions between RTD and a thermocouple. 

What is Resistance Temperature Detector (RTD)?

Resistance Temperature Detectors refers to sensor types. Its resistance changes with the change of temperature. Talking about RTD vs. Thermocouple, RTD’s resistance increases with the increase in temperature, whereas there is a decrease in thermocouple’s resistance. These sensors are passive devices, which means that RTDs do not generate output on their own. The element present in Resistance Temperature Detectors consists of a film prepared of a pure metal or a wire coil. These are comparatively immune to electrical noise and hence, are well-suited for measuring temperatures in industrial applications. 

What is the Use of Thermocouples?

A thermocouple is a sensor device that comprises two non-similar conductors. The conductors used to produce a voltage that is proportional to a difference in temperature between the conductor’s ends. In comparison to other temperature measurements, thermocouples need no external form of excitation as these are self-powered. Thermocouples measure the unfamiliar temperature of the body with reference to the other body’s known temperature. RTD and Thermocouple are user-friendly and help in getting the results rapidly. 

The diagram shows that two material wires are used in thermocouples that form a junction. It allows thermocouples to measure the high-temperature range.

Benefits of Using Resistance Temperature Detectors?

• RTDs offer accurate measurements and thus proven to be the most precise temperature sensors.

• It has tremendous sensitivity over the narrow spans.

• It has low susceptibility to RFI and EMI.

• RTDs offer stable output that lasts for longer periods.

• These offer immunization against the electrical noise. 

• The lifespan of RTDs is for many years.

Applications of Resistance Temperature Detectors

Resistance Temperature Detectors can be used in:

• Refrigeration servicing

• Micro Electronics

• Plastics processing

• Air Conditioning servicing

• Temperature measurement of air, gas, and liquid

• Petrochemical processing

• Textile production

• Stoves and grills

• Micro Electronics

• Measurement of exhaust gas temperature 

Benefits of Using Thermocouple

Due to their small size and quick response, Thermocouples are widely used in industrial applications.

• It resists vibrations and shocks.

• It is useful for a broad range of temperatures.

• Thermocouples are the most durable sensors for temperature measurements.

• It is user-friendly and retrieves the results promptly.

Applications of Thermocouples

• Thermocouples are widely used in:

• Diagnostics testing for diesel engines 

• Various gas appliances like boilers, water heaters, and ovens

• Hospital thermometers 

• Temperature sensors in thermostats 

• Gas turbine exhausts, kilns, and other industrial applications 

Different Situations Where You Prefer RTD Over Thermocouple

• Combined with Transmitters: It’s easy to combine RTD with transmitters that enable the temperature data to be directed to a remote control location. It also allows the users to view the local display of the temperature. 

• Laboratories and Industrial Purposes: In terms of accuracy when we set up RTD vs. thermocouple, RTD is much more accurate as compared to the thermocouple and hence more preferable for laboratories and industrial purposes.

• Automotive Industries: When the temperature process has a range in-between -200 to 500-degree Celsius, then industrial RTD is much superior over thermocouple. 

• Medical Electronics: When it comes to a low amount of shifts for RTD vs. thermocouple, RTD shows a very virtuous good stability and linear display as well. However, thermocouples are poor in terms of stability and hence less preferable for industrial applications.

The picture shows that thermocouples are useful to measure a high range of temperatures. However, RTD is useful for low-temperature measurements.

To sum up, the critical differences between RTDs and Thermocouples include:

What are the Differences Between RTD and Thermocouple?

A study generally performed on the displacement of the object is the displacement mechanics. 

We all like to take a shortcut in our lives or while driving to our office while getting late, so the shortest path we take is displacement.

A displacement is a vector form of the shortest distance between the initial position and the final position.

On this page, also we will discuss what is displacement, displacement definition, displacement meaning in Physics, displacement of the particle, be it having a linear motion or the circular motion.

What Is Displacement?

If you are curious to know what displacement is, look at the following diagram:

Let’s suppose that the distance between points A and B is 30 m and the shortest path between these points is along the way, which is just 16 m from your destination. If you are asked which path you will choose?

Definitely, you will travel through the 16 m path line, so this path line is the displacement (this is the displacement definition).

Displacement Definition Physics

Now, let us understand the displacement definition with the help of a known term ‘distance’:

Example 1:

Soham walks from point A to B to C. What distance, does he travel? What is the displacement?

Let’s first calculate the distance Soham travels. While calculating distance, we look at the numerical value of the distance interval between the travelled points. As we can see from the above figure that he travels from A to B, then B to C. Distance from point A to B is 4m and from B to C is 3 m. So, their sum will give us total distance as;

4 m + 3 m = 7 m

Now, it’s time to calculate displacement. Since displacement is a vector quantity, so it has both magnitude and direction. 

In our stated example, the initial point is A and the final point is C. Displacement vector is an interval between the initial and final points. As it can be clearly seen that the interval between A to C is 5m. So, our displacement vector is 5m and its direction is from point A to C.

Let’s look at another example:

Example 2:

We find distance taken by an object as;

From A to B =10 – 2 = 8m

From B to C = 10 – 2 = 8m

Then, from C to D = 10 – 6 = 4m

Total distance traveled from point A to point D is;

=>    8m + 8m + 4m = 20m

Now, we can find the final displacement by drawing a straight line from point A to the final point F. As we can see from the above graph, the object changes its position to 8m. So, the displacement is given as;

Displacement = Final position – Initial position

Displacement = 10m – 2m = 8m

Displacement Mechanics

Now, let us understand the displacement mechanics with the help of the below diagram:

Look at the image above, you can see there are two multiple paths between point P’ and P. Now, the distance that lies very close to both is indicated by the path line. This path line is nothing but displacement. 

Since displacement is indicated by a direction with the magnitude, we call this quantity a vector. A displacement vector is represented by an arrow-head, where an arrow indicates the direction and the tail follows it.

Here, we considered a field of displacement to represent the displacement mechanics, now let’s understand the displacement field.

Mechanical Displacement

A displacement field is assigning the displacement vectors for all points in a region for a body that is displaced from one position to another. 

A displacement vector specifies the position of the displacement of a particle in reference to an origin or to a previous position. 

For example, a displacement field may be used to describe the effects of deformation on a solid body that we study in the concept of stress and strain.

Before discussing displacement, the position before deformation must be defined. It is a state in which the coordinates of all points are known and described by the following function:

P_o^➝: Ω ->Q ….(1)

Where

Po^➝ is a displacement vector

are all the points of the body

Q are all the points in the space in which the body resides

Force Into Displacement

In the above equation (1), we understand that the displacement vectors point to all the directions of an object.

Most often it is a state of the body in which no force to displacement is applied, then given any other state of this body in which coordinates of all its points are described in the following manner:

v^➝ = P₁^➝ – P_o^➝…..(2)

From the above equation (2), we can see that the displacement field is the difference between two body states or positions.

and, v^➝is a displacement field, which for each point of the body specifies a displacement vector.

Dwarf Planet Meaning

So, what is a dwarf planet? As we all know that our universe seems infinitely large. Even trying to comprehend its size is profound in itself. Space is filled with a ton of fascinating objects known as heavenly bodies or celestial bodies. There are several types of heavenly bodies such as planets, stars, moons, asteroids, meteors, dwarf planets and many more. We are very tiny as compared to these objects. Some of the planets are way larger than our planet earth. We are on a continuous quest to discover these bodies based on our current technological capabilities. There are more than a billion stars in our milky way galaxy, and more than fifty such galaxies combine to form a local group. It is always fascinating to learn about these objects. 

Due to the sheer size of these bodies, we have not even discovered a tiny fraction of our galaxy. There are several mnemonics available to remember the names of the planets in our solar system and you can also make your own as per your comfort. Today we will focus on dwarf planets and find out What is a dwarf planet? Our solar system also contains a dwarf planet named Pluto. We used to count it as one of the planets, but due to some complications now it falls under the category of dwarf planets. Below we will learn about Dwarf planets, dwarf planet meaning, and look at a dwarf planets list.

What is a Dwarf Planet?

So let us start by understanding the dwarf planet definition. Dwarf planets are celestial bodies or planetary-mass objects(having a mass equivalent to a planet) that are not satellites and also do not dominate their region, unlike the regular planets. These bodies are too large to be categorized in the smaller objects and too large to be called a full-fledged planet. According to the international astronomical unit, a planet needs to meet specific criteria to be called the dwarf planet. First, it should directly orbit around the sun like other planets. Second, it needs to have enough gravity so that it can pull its mass in a spherical or round shape. Lastly, its orbit needs to be clear of small objects. 

The above criteria describe the dwarf planet’s meaning, and if a planet meets all these criteria, then it is categorized as a dwarf planet. However, the critical difference between planets and dwarf planets is in that last criteria. A regular planet has a substantial amount of mass or gravity to pull or push away the objects that obstruct its orbital path. In the case of dwarf planets, their gravity or mass is not adequate to perform this maneuver. It is challenging to pinpoint the total number of dwarf planets in the solar system(milky way). To classify or approve a celestial body as a dwarf planet, we need to observe it closely.

 (Image to be added soon)

( Dwarf Planets )

Alan Stern was the first person to introduce dwarf planets in his three-part categorization of planetary objects(having the mass equivalent to planets) in our solar system. He called them satellite planets, classical planets, and dwarf planets.  Ultimately the international astronomical union accepted the term dwarf planet in 2006. There are several known or discovered dwarf planets such as Pluto, Eris, Ceres, Haumea, and Makemake. The scientific society believes that there are still more than a hundred dwarf planets that need to be discovered. So, you must be wondering which planet is known as Dwarf planet? Let us move on to a dwarf planets list and categorize which is the dwarf planet?. 

Which is the Dwarf Planet?

Based on the dwarf planet meaning we will look at planets and determine which is the dwarf planet? Below is the discovered dwarf planets list and their discovery dates respectively.

• Pluto:- It was previously in the category of planets, but since 2006 it is considered a dwarf planet.

• Ceres:- This celestial body was also considered a planet until 2006. It was discovered in 1801. 

• Eres:- it was discovered in 2005.

• Makemake:- We classified it as a dwarf planet in 2008.

• Haumea:- discovered in 2004, announced in 2005 and classified as a dwarf planet in 2008.

How was Pluto Named a Dwarf Planet?

You must remember the mnemonic My Very Educated Mother Just Served Us Nine Pizzas for all the planets in the solar system. The last one pizzas use to represent pluto as it was considered as one of the nine planets in our solar system. It was discovered on February 18, 1930, and since then it was considered as a planet. But since 2006 the international astronomical union reclassified it as a dwarf planet. It used to come very close to the sun in its orbital path and considered an odd planet. An astronomer named Michael brown discovered a similar-sized object as pluto called Eris. Later, when the terminology dwarf planet came to being then both of these objects were reclassified into this category.   

In mechanics, elasticity is an attribute of a body by virtue of which an object regains its orientation after being subjected to an external force.

Among three states of matter, a solid is a rigid object in the universe. When this object undergoes any change in its physical orientation and structure upon external force application. There is a change in its length, volume, or shape. So when this object retains its original shape and size upon removal of external acting forces, we say that it is elastic. 

Now, let us understand what elasticity is with its applications and Hooke’s law on this concept.

What Do You Understand by the Elastic Behaviour of Materials?

When we stretch a slingshot, it has been deformed due to the applied force, and again its original shape has been regained, when we stop applying the force, which is called elasticity, that means when stress is being applied the body resists any permanent change. The body regains its original shape, and size with the removal of applied stress. Let us say that a thin steel rod has been taken for its bend. The application of force should be stopped when it bends a little. The rod does not regain its original shape. Based on the elastic and plastic nature of the materials, different types of behaviour of the material can be seen, which can be explained using Hooke’s law.

The ability of a body to resist any permanent change to it when stress is applied is known as Elasticity. Different materials show different elastic behaviour. It is very important to study the elastic behaviour of a material. Most engineering design requires knowledge of the elastic behaviour of materials in the construction of various structures like bridges, columns, pillars, beams, etc.

More on the Study of Elasticity

We know that atoms in solids are strongly bound. In these materials, atoms are surrounded by other atoms of the same kind, and they are maintained in equilibrium by interatomic forces, so let’s say, we stretch a spring in either of the ends, the particles in this spring dissolve by some distance ‘d’ and spring deforms. 

Here, we see that if we release the spring or when the deforming force is removed, interatomic interactions cause the atoms in the spring to return to their original state of equilibrium. However, sometimes spring may have a change in orientation. That’s the point, where we say that elasticity is just ideation because no substance is perfectly elastic.

Example on Elasticity – Hooke’s Law

Let us consider a beam resting at both ends subjected to a load W at its midpoint. The beam has a length l, width b, and thickness a. When a load is exerted at its midpoint, it bends as shown. In the process, the upper surface is compressed whereas the lower surface is extended. The beam will sag or deflect due to the load.

The beam bends less for a given load if the width b is greater and the length is smaller. This is due to the fact that the deflection of the beam due to the load is inversely proportional to the cube of the width and directly proportional to the cube of the length of the beam. But on increasing the width, b, unless the load is placed at the right place, there is every chance that the beam will bend. Such bending is called ‘buckling’. Hence the beam can buckle under asymmetric loading, which is the case in bridges that carry differently distributed traffic at different times. Hence to avoid this, the cross-section of the beam is chosen to be an I-shape. A large load-bearing surface and enough depth to prevent bending are being provided by this shape.

In this case, it is given as;

[delta = frac{Wl^{3}}{4bd^{3}gamma}]

Where,

δ is the sag.

Y is Young’s modulus of elasticity

Using the above equation we can easily say that to reduce the amount of bending for a certain load, Young’s modulus of elasticity of the material used must be large. Since sag is inversely proportional to the cube of depth, the depth d must be considered. But the problem faced on increasing the depth is that bending increases and this is known as buckling. Therefore, a compromise is made between the different cross-sectional shapes.

Application of Elastic Behaviour of Materials

1. The theory of elasticity is used to design safe and stable man-made structures such as skyscrapers and overbridges to make life convenient. Cranes used to lift loads use ropes that are designed so that the stress due to the maximum load does not exceed the breaking stress. It is also found that a collection of thinner wire strands when compacted together make the rope stronger than a solid rope of the same cross-section. That is the reason, crane ropes are made of several strands instead of one.

2. Structures such as bridges and tall buildings that have to support static or dynamic loads are generally constructed using pillars and beams to support them. The beams used in buildings and bridges should have to be carefully designed so that they do not bend excessively and break under the stress of the load on them. Beams and pillars are designed to remain stable and safe within the range of the maximum load they are designed to carry.

Fun Facts

1. If you can twist, bend, stretch or squeeze it, and when you let go it returns to its original shape, it’s an elastic object.

2. To a greater or lesser extent, most solid materials exhibit elastic behaviour, but there is a limit to the magnitude of the force and the accompanying deformation within which elastic recovery is possible for any given material.

3. Gases and liquids also possess elastic properties since their volume changes under the action of pressure.

4. Elasticity is the ability of a material to regain its own original shape after being stretched according to which rubber is the most elastic substance and glass will have the least elasticity.

5. When all three balls are dropped from the same height, the rubber ball will bounce the highest because it has the greatest elasticity. It gets compressed or squashed when the rubber ball hits the ground because it is very elastic, it quickly returns to its original shape.

From our above context on the elastic materials, we can say that elasticity is an opposition to change. Example: a rubber band. 

The bodies which we have taken for this purpose which is in the application of electric field results that are present in the generation of electric current. This is due to the movement of the electrons and is known as an Electrical Conductor. In such similar bodies which we took as observers the electrons are free to move around and at times inside the body and their motion which is random can be influenced by an field which is electric. 

Electric Conductors Explained

Most of the conductors which are electrical in nature are metals mainly because metals electrons which possess in the orbit which is outermost where they are most loosely held and can move around in a very easy manner. The wires which are supplying electricity to our houses are supplying energetic electrons which are fresh electrons to your house for you to use. We have to learn how to use it and we have become completely dependent on things like electricity.

Conductor Current

Case 1:The Condition Which are Normal Without Battery

• We know that the free electrons that are the valence electrons keep moving randomly.

• Next we can see that these electrons will have some of the velocity with which they keep on moving randomly inside the conductor. This is the velocity which is known as thermal velocity.

• As this entire motion which is said to be random therefore the average thermal velocity that is of electrons is 0.

Case 2: When We Apply an External Electric Field to it 

• We can easily notice here that when the battery is applied the electrons will start moving that too towards the positive end of the conductor.

• Then we will notice next that the positively charged ions get attracted towards negative ions but we can also see here that as these positively charged ions are heavy they don’t move.

• Next as we have seen that the electrons move towards the positive end they get accelerated.

• Next of all as electrons are moving in direction which is one they will collide with the positively charged ions in the path.

• The velocity which is extra whatever the electron gained by accelerating will be lost as a part by collision.

• The result which is said to be as the net result is that the electron acquires a very small amount  which is of velocity. The average of all that we have discussed is this small velocity which they have acquired is known as Drift velocity.

Flow of Electrons in a Conductor

In subjects like physics and the topic like electrical engineering we have seen a conductor which is an object or we can say the type of material that allows the flow of charge that is electrical current in one or more directions. Materials which are made of metal that are common in the electrical conductors. The current or we can say that the 

Electrical current is generated by the flow which is of negatively charged electrons and the positively charged holes and then the negative or the positive ions in some cases.

In order to remember things regarding current flow it is not necessary for one charged particle which is ultimately to travel from the machine producing the current to consuming it. Therefore the powering helps the machine. 

Essentially, we can say that what is occurring is a chain which is long of momentum transfer in between charges of mobile carriers. The model of Drude of conduction describes this process even more rigorously. This momentum which we have discussed about the transfer of model which makes metal an ideal choice for a conductor of metals. Characteristically we can say that they possess a delocalization which is related to a sea of electrons that gives the electrons that are enough mobility to collide and thus affect a momentum transfer.

As discussed in the article above the electrons that are the mover which is the primary mover present in metals.  However the devices which are said to be the  other devices such as the cationic electrolyte s which is of a battery or the photons which are mobile of the proton conductor of a fuel cell rely on charge which is positive carriers.