In our school, in the 80s of the last century, students in the lessons use the calculator forbidden. The teacher of mathematics adhered to the opinion that it is necessary to develop an oral account. Now, at the incident, I am rather inclined to agree with it. Oral skills came in handy in life ...
Today, when there is always a smartphone with a calculator at hand, the question of "calculations in the mind", it seems not so urgent. Meanwhile, in the times of bone accounts (you know how to use them?) Methods that simplified some standard calculations were invented. Now they would be called, probably, Lifehaki.
One of these "secret" methods is forgotten today A quick way to translate "meters per second" in "Kilometers per hour."
In the standard case, "meters per second" multiply by 3600 and pour to 1000 (or multiply by 36 and divided by 10). In the mind "Curve" the number multiplied by 3600 or 36 is quite difficult.
The "Secret" method is as follows: 1. Initial value in m / s multiply by 4, 2. From the result obtained, subtract 1/10 part.
Consider on the example.
Let the initial value - 22 m / s. 1. We multiply on 4 in the mind: 22 x 4 = 88. 2. Remove the 1/10 part (also in the mind): 88 - 8.8 = 79.2 (km / h). Worth the standard method: 22 x 3600 = 79200 -> 79200/1000 = 79.2 (km / h)
The results coincided. In my opinion, the "cunning" method is easier to perform. With numbers up to 10 or multiple 5, there are no wruffs. For example: 15 m / s Translated in km / h: 15 x 4 = 60, 60 - 6 = 54 (km / h). There's even decimal fractions here.
Remembered it When it was necessary to check in a child in "self-isolation" on "remote learning" The task of translation m / s km / h. Maybe it will be useful to you, the more not so much known this "lifehak". And you can teach a child: and in life it will be useful, and classmates will be surprising.
If you remember something like the same "tricky", share in the comments.
Speed measurement units are used quite often. True to different categories of objects (whether it is a living organism or an inanimate object) various values are applicable. So, to living organisms, depending on the pace of movement, meters and even centimeters per second or a minute are used.
For vehicles are characteristic of such units as kilometers per hour. In the space space is generally unthinkable for the naked eye. There they reach thousands of kilometers per second.
Based on this, it is quite often necessary to translate some indicators to others. The most common is the translation of such units as a kilometer per hour per meter per second. However, sometimes there is a need to translate other units of speed. But before the conversion of various velocity units, it is necessary to understand the ratio of such values as distance and time, since we use these two indicators.
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The ratio of units of distance and time
Before making the conversion of some speed values to others, you need to understand well what speed is.
Those. Speed is the length of the path of any object divided by the time spent by the object on the passage of this path. From here we see that we are transferring km / h in m / s or m / min, etc. I have to translate and units of distances and units of time. Next, remember the ratio of units of distance:
1 km. = 1000 m. And 1 m. = 0.001 km
As well as the ratio of time units:
1 h = 60 min. = 3600 s. And 1 s. = 1/3600 h. = 0.00028 h.
Using these quantities, you can safely translate some speeds of speed to others. The main thing is not to get confused.
Translation of meters per second to kilometers per hour
For a start, let's see how standard meters per second and kilometers per hour are translated. The first thing we derive a single speed indicator through the following ratio (for km / h and m / s):
1 km / h = 1000 m / 3600 c = 0.28 m / s.
1 m / s = 0.001 km / 0.00028 h = 3.57 km / h
As a result, we received two indicators using which you can translate some values to others. For example:
38 km / h in m / s: 38 x 0.28 = 10.64 m / s
58 m / s in km / h: 58 x 3,57 = 207 km / h
You can, of course, withdraw the translation formula immediately, without the above solutions. Consider this on the same examples.
38 km / h We translate into m / s., And 58 m / s in km / h. To do this, we write the following expression:
38 x (1000/3600) = 38 x 0.28 = 10.64 m / s
58 x (0.001 / 0.00028) = 58 x 3,57 = 207 km / h
As you can see, in the answer we got absolutely the same.
Translation of meters per second to kilometers per second
Now consider this option when we need to translate meters per second to kilometers as a second. Here we see that the unity of time remains the same, and therefore we do not need to translate. Therefore, we will translate only meters and kilometers.
Consider on the example.
How many kilometers per second will be 100 meters in sec. As we know that 1 meter contains 0.001 kilometers, then 100 meters will be 0.1 kilometers (100 x 0.001).
Since hours in seconds we do not translate, we obtain that the speed of 100 m / s will be 0.1 km / s.
How many meters per second will be 45 kilometers to sec. Since 1 kilometer is 1000 meters, then 45 must be multiplied by a thousand. We receive as a result of 45,000 meters. We will not translate seconds and then we get that 45 km / s is equal to 45 000 m / s.
As you can see everything is pretty easy. This is the simplest mathematics, which is still in elementary school. But if you do not want to count by postponing notepad and handles, then go to the Internet, where you open any online calculator, and make the necessary translation operations there.
You can download the calculator to myself and on the smartphone. They work without connecting to the Internet and you can in any place quickly convert the values you need.