Straight line: How many points are needed to make a straight line?

straight line
A straight line is likely to intercept the axes

Equation of a straight line

In order to determine the equation and the graph of a straight line you just need two conditions. It could be two points, or one point and the slope, or intercepts from the axes etc.

If a straight lines passes through points (x1,y1) and (x2,y2) then the equation of the line is as follows:


If a line passes through point (x1, y1) and has the slope of value m, then its equation is:


If a straight line has intercepts of values a, b respectively from X and Y axes then its equation would be:


Now if a straight line has a distance of p from the origin and the perpendicular line-segment from the origin to it makes an angle of Q with the positive X-axis, then its equation is:


As you can see from the above analysis that two conditions are enough to determine a straight line.

Now I am going to create a philosophy of the above example. A person’s character is like a straight line, with a very few exceptions. Suppose you get introduced with a new person; you may find him a nice person, or an average one. Before you finally trust him/her with something, be sure to check him at least twice. Pretend that you assigned him something. If he repeat the same kind of mistake, then you can conclude that he is an erroneous person. If you trust someone with something and find that he breaks your trust twice, then surely he’s a person not to be trusted.

Personal experience stating the reason for bringing this up

I present this example because recently I have gone through an experience which very much resembles the straight-line case. The person who disappointed me is none other than my FIL. Back in 2011 I graduated and joined a publications company, everything was going fine for me. That’s when my FIL advised me to leave that job and promised to get me a better one. I listened to him, but he was unable to fulfill his promise (couldn’t find me a job that he promised). I was very frustrated and financially devastated for a couple of months. However I recovered myself and found myself a new job.

Recently I relied on my FIL for another matter. He has been repeatedly suggesting me to buy some land now that I have some money in my hand. I listened to him. After all I gotta ensure my wife’s and my child’s future (recently I became a father). So I asked my FIL to find me some suitable land, he did that. Although the land is pure and not at all controversial, but the owner might not be. My FIL proposed me to make some ‘advance payment’ and then at a later time pay the rest of the money. I agreed to do that and paid the advance money. The problem is that the ‘advance deed’ was a open one and now-a-days no open (unregistered) deed is accepted at court. So at the end of three months period (as depicted in the deed) I can’t possibly legally put pressure on the owner lady to accept the rest of the money and thus register the land in my name.

The conclusion and decision

This time too I got caught because of my FIL, because he should’ve known that no open deeds are accepted at court now-a-days. Now I’m running the risk of losing my advance money which is a pretty big amount for me. Then again I can lodge a money-suit against that lady if she tries to play very tricky. The point is that I’m never going to trust and rely on my FIL again. Like a straight line I’ve got two points about him and now I am able to draw that line which would depict his character: HE’S NOT TO BE TRUSTED.

You might also read: Series connection in real life: the reason why series connection might be hazardous

voltage pressure and temperature relationship

Consider two charged bodies – direction of flow of charge between them doesn’t depend on the relative amount of charges on the bodies. It depends on the potential difference between them. It is a misconception that if they are connected by a wire the body with more charge will lose charge and the other will gain charge until the amount of charge is equal on both the bodies. voltage pressure and temperature relationship.

Actually the thing is that charge will flow from one body to other if the charge density on the bodies are unequal. It will keep flowing until the charge density is equal on both the bodies. Charge density is a measure of electric potential. The more is the charge density on a particular object, the more is its electric potential. The two charged bodies will transfer charge from one to another because charge constitutes of elections. They repel one another due to having same kind of charge.

A practical life example

Now consider two rooms with unequal space and the number of people in those might be equal or unequal. Just think that density of people in those two rooms are unequal. If the two rooms are connected by a passage, some people will have a tendency to migrate from one room to another. Because too many people in a single room makes it congested and inhalation of the people gets obstructed. The shift of people from one room to another will continue until the density of people becomes almost equal on both the rooms. voltage pressure and temperature relationship

You  might also read: Series connection in real life: the reason why series connection might be hazardous

The same thing is applicable for pressure. If we connect two cylindrical containers of water by a pipe at their lower end, water will definitely transfer from one to another. But the direction of flow will depend on relative height of water-column in the containers, not on the amount of water in them. If the thick container has more water in it but lower height of water column then it will lose water, the other will gain.

Role of temperature in heat science

Now about temperature. If we connect two bodies thermally, one will lose heat and the other will gain. This transfer of heat and direction of flow will not depend on relative amount of heat in the two bodies. it will depend on relative temperature, or temperature difference. The hotter body (the one with greater temperature) will lose heat even if it might be the one with less amount of heat. The other will gain heat if it has lower temperature, even if it is the one with greater amount of heat. Here comes the idea of ‘Heat capacity’. The second body will gain further heat although it already has greater amount of heat, just because its heat-capacity is greater. voltage pressure and temperature relationship

voltage pressure and temperature relationship
voltage and pressure relationship

Series connection in real life: the reason why series connection might be hazardous

Series connection hazardous real life
series connection bulbs

A couple of bulbs connected in series, if one of them is fused, none of them will glow anymore. And you can not say for sure which one is fused, unless you manually check each and every of them. Series connection hazardous real life. These are the hindrances and drawbacks of series connection.

Then again, there are some advantages too, like: you can switch on or off all the lights or electrical appliances in series just with a single switch. Series connection is not effective, when there is a significant voltage drop in each appliance. For example, if the bulbs used in street-lighting are such in structure that each causes a small drop in potential, then there will be gradual drop in effective potential difference for the rest of the bulbs and thus they will glow dimmer. So when planning to put a few appliances in series, you have to keep these factors in mind. Series connection hazardous real life

You might also read: Similarity between voltage, pressure and temperature

A real-life example of series connection

Now I am going to give an example of series connection-type scenario in real life. You know about youtubing. The job of uploading videos to one’s youtube channel and monetizing those and thus earning money is called youtubing. In order to do successful youtubing, you must not (i) steal someone else’s video (ii) get community strikes (iii) use misleading metadata (iv) post bad comments in someone else’s videos that can be marked as spam and many other factors. If any of these goes against the rules, Google might simple terminate your channel without showing any reason.

This is why, a Youtube user, when has his account suspended, often claims that they did nothing wrong. Actually the thing is that they just don’t realize what they did wrong. It’s like that ineffective series connection where at least one appliance is out of order and you don’t know which one it is. Series connection hazardous real life