Name: scalar quantities in physics
Uploaded: 2023-09-22T11:49:38.000Z
Duration: 1 min 21 s
Channel: JoVE
Description: Scalar quantities in physics have size only. They do not include direction. This makes them different from vector quantities. Common scalar examples include mass, temperature, time, and energy. Each one can be described with a number and a unit. Because direction is not part of the value, scalars are often easier to compare and measure.

Wielkości fizyczne, takie jak czas, masa i odległość, mają wielkość, ale nie mają kierunku. Takie wielkości nazywane są wielkościami skalarnymi.
Są one wyrażone jako wartość liczbowa, po której następuje jednostka fizyczna. Na przykład masa jabłka wynosi 100 g. 
Skalary różnią się od wektorów, ponieważ wektory mają zarówno wielkość, jak i kierunek.
Na przykład masa obiektu zależy od ilości materii w substancji i jest wielkością skalarną. Natomiast jego waga, czyli siła wywierana przez grawitację Ziemi, jest wielkością wektorową.
Podobnie odległość jest wielkością skalarną, podczas gdy przemieszczenie, czyli zmiana położenia obiektu, jest wielkością wektorową.
Skalary są oznaczone kursywą.
Skalary mogą być ujemne, takie jak ładunek elektronu lub odczyt skali termometru.
W tym przypadku znak minus reprezentuje punkt na skali lub charakter jednostki.
W przypadku termometrów w stopniach Celsjusza i Fahrenheita skale wskazują zero w różnych punktach. W związku z tym ujemna temperatura jest również odczytywana przy różnych odczytach skali.

wprowadzenie do skalerów

Wiele znanych wielkości fizycznych można całkowicie określić, podając jedną liczbę i odpowiednią jednostkę. Na przykład „lekcja trwa 50 minut”, lub „zbiornik paliwa w moim samochodzie mieści 65 litrów” albo „odległość między dwoma słupkami wynosi 100 m”. Wielkość fizyczna, którą można w ten sposób całkowicie określić, nazywana jest wielkością skalarną. Słowo „skalar” jest synonimem „liczby”. Czas, masa, odległość, długość, objętość, temperatura i energia to tylko niektóre przykłady wielkości skalarnych.

Wielkości skalarne mające te same jednostki fizyczne można dodawać lub odejmować, zgodnie ze zwykłymi zasadami algebry liczb. Na przykład zajęcia kończące się 10 min wcześniej niż 50 min trwają 50 min − 10 minut = 40 minut. Podobnie, gdy do porcji kukurydzy o wartości energetycznej 60 kcal dodamy porcję pączków o wartości energetycznej 200 kcal, otrzymamy 60 kalorii + 200 kalorii = 260 kalorii energii. Kiedy mnożymy wielkość skalarną przez liczbę, otrzymujemy tę samą wielkość skalarną, ale o większej (lub mniejszej) wartości. Na przykład, jeśli wczorajsze śniadanie miało wartość energetyczną 200 kalorii, a dzisiejsze śniadanie ma cztery razy więcej energii niż wczorajsze, to dzisiejsze śniadanie ma 4 × 200 kcal = 800 kalorii energii. Dwie wielkości skalarne można również pomnożyć lub podzielić przez siebie, tworząc pochodną wielkość skalarną. Na przykład, jeśli pociąg pokonuje odległość 120 km w ciągu 1 godziny, jego szybkość wynosi 120 000 m/3 600 s = 33 m/s, gdzie szybkość jest pochodną wielkości skalarnej otrzymaną poprzez podzielenie drogi przez czas.

Ten tekst jest adaptacją <a href="https://openstax.org/books/university-physics-volume-1/pages/2-1-scalars-and-vectors">Openstax, University Physics, tom 1, sekcja 2.1: Skalary i wektory.</a>

Wprowadzenie do skalerów

Wiele znanych wielkości fizycznych można całkowicie określić, podając pojedynczą liczbę i odpowiednią jednostkę. Na przykład "lekcja trwa [...]

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Mechanical Engineering

Inżynieria mechaniczna

Unit 1

Jednostka 1

Physics Basics

Podstawy fizyki

KEY TERMS AND CONCEPTS

Kluczowe terminy i pojęcia

Introduction to Scalers

scalar quantities in physics

Scalar quantities in physics have size only. They do not include direction. This makes them different from vector quantities.

Common scalar examples include mass, temperature, time, and energy. Each one can be described with a number and a unit. Because direction is not part of the value, scalars are often easier to compare and measure.

Scalar Quantities in Physics

introduction to scalers

Scalar quantities in physics have size only. They do not include direction. This makes them different from vector quantities. Common scalar examples include mass, temperature, time, and energy. Each one can be described with a number and a unit. Because direction is not part of the value, scalars are often easier to compare and measure.

vector or cross product

Cross Product of Two Vectors

The cross product of two vectors gives a new vector that is related to both original vectors. It is also called the vector product. In many physics problems, this operation helps describe quantities that depend on direction as well as size. The result of a cross product has a direction set by the two input vectors. It is not the same as ordinary multiplication. The transcript focuses on the vector or cross product as a core vector operation students use when working with vectors in science.

introduction to vectors

Vectors in Motion and Direction

Vectors describe quantities that have both size and direction. They are used in physics to show how motion, force, and other quantities act in space. A vector can be represented with an arrow. The length of the arrow shows the size, and the arrowhead shows the direction. This makes vectors useful for comparing how one quantity points relative to another. Scalars are different because they have size only and no direction. Understanding the difference between vectors and scalars is an important...

units and standards of measurement

Measurement Units, Standards, and SI Basics

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accuracy and precision

Measurement Errors, Accuracy, and Precision

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rules of significant figures

Counting Significant Figures in Measurements

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random and systematic errors

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position and displacement

Tracking Motion with Position and Displacement

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position and displacement vectors

Using Vectors to Describe Motion

Position and displacement vectors describe motion in physics. A position vector shows where an object is located relative to a chosen origin. A displacement vector shows how far and in what direction the object moves from one point to another. These vectors are useful because they give a clear way to track movement in space. The video connects position and displacement to the idea of a reference point and shows how direction matters as much as distance. That makes them important for describing...

mass and weight

How Mass Differs from Weight

Mass and weight are related, but they are not the same. Mass is the amount of matter in an object. Weight is the force of gravity acting on that object. This difference matters because mass stays the same even when gravity changes. Weight can change if the gravitational pull changes. A person or object therefore has the same mass, but not always the same weight. The terms are often used in everyday speech as if they mean the same thing. In physics, they describe two different ideas.

acceleration due to gravity on earth

Free-Fall Acceleration on Earth

Free-fall acceleration on Earth describes how fast an object speeds up when gravity is the only force acting on it. Near Earth’s surface, this acceleration is nearly constant for many everyday situations. Gravity pulls objects toward Earth and gives them downward acceleration. This motion is often written as g, and it helps explain why falling objects gain speed as they move downward. The value of g is commonly used in physics to predict the motion of objects dropped or released near the...

tension

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gravitational force

How Gravity Acts Between Objects

Gravity is a force that pulls objects toward one another. On Earth, this force gives objects weight and keeps people, water, and other materials from drifting away. It also helps explain why planets and moons stay in motion around larger bodies. The strength of gravitational force depends on the masses of the objects involved. Larger masses create a stronger pull, while smaller masses create a weaker one. The distance between objects also matters, because gravity becomes weaker as objects move...

key terms and concepts

Learn how scalar quantities are used in physics, with clear examples like mass, temperature, time, and energy for high school students.

Scalar Quantities in Physics | JoVE K12

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Scalar Quantities in Physics

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