Are there any Difference between speed and speed ? If you ask any individual on the street, you will say that the terms are synonymous, which could be true in a non-scientific context.
In fact, the Dictionary of the Royal Spanish Academy expresses that speed is"lightness, speed". However, in physical , There are specific concepts for each of these terms.
Speed is a vector magnitude, because it has a module, a direction and a sense. Speed is a scalar magnitude, since it lacks direction and meaning.
This is the essence of the difference between these two terms. It will then go a little deeper to establish a clearer delineation between the concepts of speed and speed.
Differences and similarities between speed and speed
Differences
- Velocity is the resulting quotient between the traveled space and the elapsed time, referring to the direction of movement. The speed, on the other hand, is the result of the division between space and time, without taking into account the direction.
- Velocity is a vector magnitude, while velocity is a scalar magnitude.
- Speed is expressed in kilometers per hour, plus direction (north, south, east, west); For example 55 km / h west. On the other hand, the speed is expressed in kilometers per hour; For example 55 km / h.
- You could say that speed is speed with direction and direction.
Similarities
- Both speed and speed are physical magnitudes.
- Both are derived quantities, since they result from the combination of two fundamental magnitudes.
- Both result from the relationship between space and time.
Concepts of speed and speed
Speed
To understand the concept of speed it is necessary to know two other terms: space and time, fundamental physical magnitudes.
In relation to speed, space is the magnitude that represents the length of the distance traveled by a mobile. For its part, time is the amount that represents the amount of seconds, minutes or hours a mobile uses to travel a distance.
These two fundamental physical quantities are related resulting in a derived quantity, velocity. In this sense, it could be said that the speed is the result of the division of space traveled by a mobile between the time spent to travel it.
However, the concept presented above is also the concept of speed. Then, to speak of speed, the definition must include two additional elements: the direction and the direction of the displacement. It is by these two elements that the velocity constitutes a vectorial magnitude.
With regard to direction and direction, speed takes into account the point of origin and point of arrival; This is reflected by an arrow on the unit of measure or with the letter corresponding to the coordinate.
Speed = traveled space / time used ( T ) + Direction and direction V = and N, S, E, O.
Speed can be expressed using any unit of space and time. In the international system (SI), the speed unit is the meter per second, which is transcribed m / s.
The smallest measurements are expressed in the cegesimal system (SGS), centimeters per second, which is written c / s. Finally, if the speeds are very large, the kilometer per hour (km / h) or kilometer per second (km / s) is used.
Physical quantities
The physical magnitudes are the characteristics of a phenomenon that can be measured; Length, velocity, and time are some examples of magnitudes.
Measuring a magnitude means comparing it with another standard magnitude that is taken as a unit. The result of this measurement is an amount followed by the unit used, for example 6 meters (length), 7 km / h north (Speed) and 24 hours (time).
Physical magnitudes can be fundamental or derived. The fundamental magnitudes are defined through specific scientific standards and particular measuring instruments; Length and mass are examples of these.
On the other hand, the derived quantities are delimited by mathematical formulas that relate two or more fundamental magnitudes; Speed and speed are derived quantities.
Vector Magnitudes
A vector magnitude is one that is determined when its module is known (its value in numbers followed by the unit of measure), its direction and its direction. The speed, the force , Acceleration and magnetic fields are vector magnitudes.
The vector quantities are expressed through vectors. The vectors (word from Latin and meaning"leading") are segments of a line, similar to an arrow, consisting of a module, a direction and a direction.
Speed
Speed is a physical magnitude. This, as with speed, refers to the relation between the distance traveled and the time that was used, which makes it a derived quantity. However, unlike speed, it is not a vector magnitude but scalar, since it does not take into account the aspect of the direction.
Speed can be of two types: instantaneous or averaged.
- Instant speed . It refers to the speed of a mobile at any given time. To determine this speed, simply see the meter of the mobile.
- The average speed . It refers to the average speed of moving a mobile. The formula for calculating average speed is similar to speed; However, does not include address.
- Speed = space traveled / time used
- R = e / t
Example of speed calculation
Now, let's put these formulas into practice with an example. During the holidays, Homer traveled in his car a distance of 220 km and this trip took four hours. What is the average speed?
To calculate the speed, we take the formula of this, according to which the speed is equal to the space traveled between the time used.
- Formula : R = and.
- Data E: 220 km and t: 4 h.
- Procedure: R = 220 km / 4h = 55 km / h
Speed of movement of some mobiles. This means that Homer's car had an average speed of 55 km / h.
This does not mean that he traveled at a constant speed of 55 km / h, since he most likely stopped at some point along the way; Moreover, they do not take into account the moments in which it could have accelerated or decelerated.
- Humans walk with an average speed of 5 km / h.
- A person trots with an average speed of 10 km / h.
- Professional athletes can run with a speed of 10.24 m / s at short distances (such as 200 meters flat).
- A person on a bicycle moves at an average speed of 20 km / h.
- The cars move at an average speed of 104 km / h on motorways.
- A 747 has an average speed of 904 km / h.
Scalar magnitudes
The scalar magnitudes are those that are determined by its numerical value and its unit of measurement. Some examples of scalar magnitudes, besides the speed, are mass, temperature, volume, work and density.
Clarification of the difference between speed and speed
Having studied the concepts of both terms, it can be seen that what is generally termed speed is actually speed.
For example, one should not say that a car moves at a speed of 100 km / h if the direction the car is taking is not stated, because it would be speaking of speed.
The correct thing would be to say that a car moves at a speed of 100 km / h West, for example. This last element (the coordinate) is the one that gives the vectorial character to the speed, which differentiates it from the speed, which is of scalar nature.
However, in non-scientific fields, one can speak of speed and speed indistinctly, that is, they can be used as synonyms.
References
- Velocity vs. Rapidity - What's the difference. Retrieved on April 20, 2017, from wikidiff.com.
- What's the Difference between Speed and Velocity? Retrieved on April 20, 2017, from wired.com.
- Speed and Velocity. Retrieved on April 20, 2017, from physicsclassroom.com.
- What's the difference between speed and velocity. Retrieved on April 20, 2017, from quora.com.
- Speed or Velocity. Retrieved on April 20, 2017, from edinformatics.com.
- Difference between speed and velocity. Retrieved on April 20, 2017, from physics.stackexchange.com.
- Rogers, Kara (2016). What's the Difference Between Speed and Velocity. Retrieved on April 20, 2017, from britannica.com.