Formula "Speed, time, distance." How to solve problems?

Let's turn the physics lesson into an exciting game! In this article, our heroine will be the formula "Speed, time, distance." Let's analyze each parameter separately, give interesting examples.

Speed

What is "speed"? One can observe how one car rides faster, another one is slower; One person is walking fast, the other is in no hurry. Cyclists also travel at different speeds. Yes! It is speed. What is meant by it? Of course, the distance that the man passed. Drove the car for a certain time. Let's say that a person's speed is 5 km / h. That is, for 1 hour it went 5 kilometers.

How to find speed, time, distance? Let's start with speed. Look carefully, what is it measured in? Naturally, km / h, m / s. There are other units of measurement, for example, km / s (in cosmonautics), mm / h (in biochemistry). Pay attention to the sign "/" and after. First, it means "fraction", which means that in the numerator - mm, km, m, in the denominator - h, s, min. Secondly, it seems like a formula, is not it? Kilometers, meters - distance, length, and hour, second, minute - time. Here's a tip for you. To make it easier to remember how to find the speed, look not at the unit of measurement (km / h, m / s). In one word:

V = S / t = km / h.

Time

What is time? Of course, it depends on the speed. For example, you wait at the doorstep of your mother's house and your older brother. They're coming from the store. The brother came much earlier. Mom had to wait another 5 minutes. Why? Because they went with different speeds. Of course, in order to quickly reach your destination, you need to add speed: speed up the step, put pressure on the "gas" in the car more forcefully, accelerate on the bike. Only with haste be careful and alert to not crash into someone or into something.

How to find time? Speed has a clue - km / h. And what about time? First, time is measured in minutes, seconds, hours. The formula "speed, time, distance" here is transformed as follows:

Time t [sec, min, h] = S [m, mm, km] / v [m / s, mm / min, km / h].

If you convert a fraction according to all the rules of mathematics, reduce the parameter of distance (length), then only a second, minute or hour will remain.

Distance, distance traveled

It will be easier to navigate, most likely, to motorists who have a mileage meter in the car. They will be able to determine how many kilometers have passed, and also know the speed. But since the motion is uneven, then it will not be possible to establish a precise travel time, if only we take the average velocity.

The formula for the path (distance) is the product of speed and time. Of course, the most convenient and accessible option is time. Everybody has a watch. The pedestrian speed is not strictly 5 km / h, but approximately. Therefore, there may be an error. In that case, you'd better take a map of the area. Notice the scale. It should be indicated how many kilometers or meters in 1 cm. Attach the ruler and measure the length. For example, from home to music school is a direct road. The segment was 5 cm. And on the scale it is indicated 1 cm = 200 m. Hence, the real distance is 200 * 5 = 1000 m = 1 km. How much do you spend this distance? In half an hour? In technical terms, 30 min = 0.5 h = (1/2) h. If we solve the problem, it turns out that you go with a speed of 2 km / h. The formula "speed, time, distance" will always help you solve the problem.

Do not miss it!

I advise you not to miss very important points. When you are given a task, look carefully at what units of measurement parameters are given. The author of the task can cheat. Will write in given:

The man drove along the sidewalk on a bicycle 2 kilometers in 15 minutes. Do not rush to solve the problem immediately by the formula, otherwise you will get nonsense, and the teacher will not count it for you. Remember that in no case should you do so: 2 km / 15 min. Your unit of measurement will be km / min, not km / h. You need to achieve the latter. Translate the minutes into hours. How to do it? 15 minutes is 1/4 hours or 0.25 hours. Now you can safely 2km / 0.25h = 8 km / h. Now the problem is solved correctly.

That's so easy to remember the formula "speed, time, distance." Just follow all the rules of mathematics, pay attention to the units of measurement in the task. If there are nuances, as in the above example, immediately translate into a system of SI units, as expected.