Let us consider, rocket of mass m₀ take off with velocity v₀ from ground. Let the fuel burnt at the rate of dm/dt and burnt gases eject with velocity u w.r.t. rocket.
Let at any instant t, v be the velocity of rocket and m be the mass of rocket. Therefore velocity of burnt gas ejected w.r.t. ground is (v – u). As the fuel burns at the rate of dm/dt, therefore in time dt, dm mass of the fuel will burn and velocity of rocket increases by dv.

Here m is the mass of rocket and dm is the mass of gas ejected. As the fuel burns the mass of rocket decreases. Therefore, to calculate the velocity of rocket at any instant in terms of mass of rocket, dm must be replaced by ‘dm’.


 

Ancient stories of Mesopotamia are valuable sources of information. As per the stories, Mesopotamia is situated between two rivers, the Tigris and Euphrates. Mesopotamia was one of the advanced civilizations of its time. Its society was divided into three classes, i.e.

1. The upper class
2. The middle class and
3. The lower class

People belonging to upper classes led a life full of comforts and luxury and enjoyed special privileges. Agriculture was the main occupation of the people. Their life was normally prosperous. Religion was an important part of their life and people worshiped many gods and goddesses. Shamas was their main God. It was the Sun. Ziggurat was the name given to Sumerian temples.

Another description from the Bible: According to the Bible, the flood was meant to destroy all forms of life on the earth. However, God chose a man, Noah, to ensure that life could continue after devastating flood on the earth. Noah, built a huge boat, an ark. He took a pair each of all known species of animals and birds on the board, the arks which survived the flood. When other things were destroyed by the flood, his boat remained safe along with all the species. Thus began a new life on the earth. There was a similar striking story in Mesopotamian tradition, where the principal character was called Ziusudra or Utnapishtim.

So the important point about circular arrangement is as follows:

1. If the clockwise and counter clockwise orders CAN be distinguished then total number of circular permutation of n elements taken all together = (n-1)!
2. If the clockwise and counter clockwise orders CANNOT be distinguished then total number of circular permutation of n elements taken all together = (n-1)! / 2

Example of indistinguishable case is, if you consider 5 diamonds and you want to make a necklace. In this case 5 diamonds can be arranged in a circle in (5-1)! = 24 ways. But in case of forming a necklace the clockwise and counter clockwise arrangements cannot be distinguished. So the total circular permutation in this case = (5-1)! / 2 = 4! / 2 = 12 ways.

When the author’s parents were settled in the city, they called the author and grandmother to come there. That was the turning point. Though the author and grandmother shared the same room, she did not go with him to the school. She gradually remained away from his activities and him.

Taplow is a boy of sixteen. He is pure at heart. He is a boy with no whims and fancy of his own. It is his frank nature which make us appreciate him all the more. It is great to watch that even after absenting himself from school for a day, he is ready to wait the next day to meet his teacher. His patience is all the more most attractive feature. Taplow paints before us a picture of a boy with divine nature. Inspite of having many good qualities Taplow is also good at flattery. He is waiting for the teacher because he wants extra marks for the test. Still inspite of follies he behaves in a simple, innocent manner. Infact he has not been touched by modernism and has a pure, serene heart.

Disadvantages of Social Media

Despite having such unique advantages, social media is considered to be one of the most harmful elements of society. If the use of social media is not monitored, it can lead to grave consequences.

It is harmful because it invades your privacy like never before. The oversharing happening on social media makes children a target for predators and hackers. It also leads to cyberbullying which affects any person significantly.

Thus, the sharing on social media especially by children must be monitored at all times. Next up is the addition of social media which is quite common amongst the youth.

This addiction hampers with the academic performance of a student as they waste their time on social media instead of studying. Social media also creates communal rifts. Fake news is spread with the use of it, which poisons the mind of peace-loving citizens.

In short, surely social media has both advantages and disadvantages. But, it all depends on the user at the end. The youth must particularly create a balance between their academic performances, physical activities, and social media. Excess use of anything is harmful and the same thing applies to social media. Therefore, we must strive to live a satisfying life with the right balance.

Advantages of Social Media

When we look at the positive aspect of social media, we find numerous advantages. The most important being a great device for education. All the information one requires is just a click away. Students can educate themselves on various topics using social media.

Moreover, live lectures are now possible because of social media. You can attend a lecture happening in America while sitting in India.

Furthermore, as more and more people are distancing themselves from newspapers, they are depending on social media for news. You are always updated on the latest happenings of the world through it. A person becomes more socially aware of the issues of the world.

In addition, it strengthens bonds with your loved ones. Distance is not a barrier anymore because of social media. For instance, you can easily communicate with your friends and relatives overseas.

Most importantly, it also provides a great platform for young budding artists to showcase their talent for free. You can get great opportunities for employment through social media too.

Another advantage definitely benefits companies who wish to promote their brands. Social media has become a hub for advertising and offers you great opportunities for connecting with the customer.

Appa-mam was an ascetic or Sannyasi.When the writer asked him where he had been all these days he said that he had been meditating in the mountains. He was an easy-going man he was quite lazy he found newspapers interesting and chairs comfortable. Although he claimed to be a Sanyasi there was nothing spiritual about him. while seated in an easy chair he smoked a bidi. he did not look spiritual at all. Appa-mam was quite funny and intriguing. he lived comfortable he did nothing useful to himself or to others .the writer and others think that he was a charlatan. He stole things from the house and give them to others we have no proof that he gave these things to the needy people.

The grandmother used to feed street dogs with pieces of chapattis when the grandmother and grandson duo returned home from the ‘templeschool’. At a later stage, in the city, when the author was engrossed in his higher studies, she used to spend some time feeding birds like sparrows. They had become so friendly with her that they would perch on her legs.

When the grandmother died, thousands of sparrows sat around the corpse without any chirping, all in silence. They did not touch the bread crumbs which the author’s mother had thrown for them. They flew away quietly when the dead body was carried off and never came back.

Bank Reconciliation Statement is a record book of the transactions of a bank account. This statement helps the account holders to check and keep track of their funds and update the transaction record that they have made. Bank Reconciliation statement is also known as bank passbook. The balance mentioned in the bank passbook of the statement must tally with the balance mentioned in the cash book. In the statement, all the deposit will be shown in the credit column and withdrawals will be shown in the debit column. However, if the withdrawal exceeds deposit it will show a debit balance (overdraft).

When a particle is thrown obliquely near the earth’s surface, it moves along a curved path under constant acceleration that is directed towards the center of the earth (we assume that the particle remains close to the surface of the earth). The path of such a particle is called a projectile and the motion is called projectile motion. Air resistance to the motion of the body is to be assumed absent in projectile motion.

In a Projectile Motion, there are two simultaneous independent rectilinear motions:

1. Along the x-axis: uniform velocity, responsible for the horizontal (forward) motion of the particle.
2. Along y-axis: uniform acceleration, responsible for the vertical (downwards) motion of the particle.

We observe the different features such as roads, railways, markets and other elements created by human beings.

They are dissimilar.

All these cultural features should be included in the study of geography because all these features are on the earth. The earth has always been seen as the home of human beings and we study all these features about the earth.