Name: how mass differs from weight
Uploaded: 2023-09-22T11:49:39.000Z
Duration: 1 min 19 s
Channel: JoVE

물체의 질량은 물체가 포함하고 있는 물질의 양을 측정한 것이며 그 안에 있는 원자의 수에 따라 달라집니다.
그것의 무게는 지구나 달과 같은 더 큰 물체 중 가장 가까운 물체에서 작용하는 중력입니다.
가해진 힘에 반응하여 물질의 양이 변하지 않기 때문에 물체의 질량은 일정하게 유지됩니다.
그러나 무게는 위치에 따라 다릅니다. 지구에 있는 물체는 화성이나 달에 있는 물체와 무게가 다르지만 질량은 동일하게 유지됩니다. 무게 변화는 중력이 작용하기 때문에 가속도의 차이 때문입니다.
질량은 결코 0이 될 수 없지만 중력이 작용하지 않으면 무게는 0이 됩니다. 이 관찰과 뉴턴의 제2법칙을 사용하면 질량이 m인 물체의 무게는 벡터 g를 곱한 값입니다.
즉, 물체의 질량이 클수록 무게도 커집니다. 질량은 스칼라 양이지만 무게는 지구 중심을 향하는 벡터입니다.

질량과 무게

질량과 무게는 일상 대화에서 종종 같은 의미로 사용됩니다. 예를 들어,   의료 기록에는 체중이 킬로그램 단위로 표시되는 경우가 많지만 정확한 뉴턴 단위는 표시되지 않습니다. 그러나 물리학에서는 중요한 차이점이 있습니다. 무게는 지구가 물체를 당기는 힘입니다. 그것은 지구 중심으로부터의 거리에 달려 있습니다. 위치에 따라 변하지 않는 질량과 달리 지구 표면을 벗어나면 무게가 극적으로 변합니다. 예를 들어 달에서는 중력으로 인한 가속도가 1.67m/s2에 불과한 데 비해 지구에서는 9.8m/s2입니다. 따라서 1.0kg의 질량은 지구에서는 9.8N의 무게를 가지지만 달에서는 약 1.7N에 불과합니다. 그러나 물체의 질량은 지구 표면, 궤도 또는 달 표면에서 동일합니다.

물체를 떨어뜨리면 지구 중심을 향해 가속됩니다. 뉴턴의 두 번째 법칙은 물체에 가해지는 알짜 힘이 물체의 가속도에 영향을 미친다고 명시합니다. 공기 저항이 무시할 수 있는 것으로 간주되면 낙하하는 물체에 작용하는 알짜 힘은 일반적으로 무게로 알려진 중력, 또는 질량이 'm'.

무게와 질량은 밀접하게 관련되어 있지만 서로 다른 물리량입니다. 질량은 물체의 고유한 속성입니다. 그것은 물질의 양이라고 볼 수 있습니다. 대부분의 사례에는 물체의 무게가 지구상의 물체 위치에 따라 최소 값으로 달라지는 지구에서 발생하기 때문에 질량을 무게와 동일시하려는 실수를 할 수 있습니다. 또한 물체에 포함된 모든 원자와 분자를 세고 식별하는 것이 어렵기 때문에 이러한 방식으로 질량이 결정되는 경우는 거의 없습니다.

이 텍스트는<a href="https://openstax.org/books/university-physics-volume-1/pages/5-4-mass-and-weight"> Openstax, 대학 물리학 1권, 섹션 5.4: 질량과 무게.</a>

질량과 무게는 일상 대화에서 종종 같은 의미로 사용됩니다. 예를 들어, 의료 기록에는 종종 체중이 킬로그램으로 표시되지만 결코 ...

Education

교육

JoVE Core

Mechanical Engineering

기계공학

Unit 1

제1단원

Physics Basics

물리학 기초

KEY TERMS AND CONCEPTS

주요 용어 및 개념

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. Understanding both helps students read science problems and compare objects more accurately.

How Mass Differs from Weight

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.

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

Measurement units, standards, and SI basics help scientists describe physical quantities clearly. A unit gives a number meaning, while a standard provides a fixed reference for that measurement. Together, they make results easier to compare and understand. The International System of Units, or SI, is the most common measurement system in science. It uses agreed-upon base units for common quantities. These standards reduce confusion when measurements are shared across labs, classrooms, and...

accuracy and precision

Measurement Errors, Accuracy, and Precision

Measurement errors can affect how close a result is to the true value and how consistent repeated results are. Accuracy describes how close a measurement is to the accepted or true value. Precision describes how close repeated measurements are to one another. A result can be accurate, precise, both, or neither. A set of measurements may cluster tightly together and still be far from the true value. Another set may include values spread out from one another, even if one of them is close to the...

rules of significant figures

Counting Significant Figures in Measurements

Significant figures help students record measurements with the correct level of precision. They show which digits in a number are meaningful and which only help place the decimal point. In science class, this idea matters when writing and comparing measured values. The rules for significant figures explain how to count these digits in different numbers. Some digits are always counted, while others depend on where they appear in the number. Learning the rules makes it easier to report answers...

random and systematic errors

Measuring Error in Scientific Data

Random and systematic errors affect scientific measurements. Random errors cause values to spread around the true value. They make repeated measurements less consistent. Systematic errors shift measurements in the same direction each time. Understanding both kinds of error helps students judge data quality. Random error can come from small changes during measurement. Systematic error can come from a biased tool or method. Scientists look for these patterns so they can improve results and...

position and displacement

Tracking Motion with Position and Displacement

Position and displacement are key ideas in straight-line motion. Position tells where an object is located compared with a chosen starting point, called the origin. Displacement describes how far and in what direction the object has moved from its starting position. These ideas help describe motion clearly. Position can change as an object moves. Displacement focuses on the change in position, not just the path taken. That makes it useful for comparing motion in a simple and precise way.

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

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

Tension in Ropes and Strings

Tension is the pulling force carried by a rope, string, or cable when it is stretched by a load. In physics, this force acts along the length of the object and pulls away from the objects at each end. A stretched rope can support a hanging mass because the tension in the rope balances the weight of the load. The same idea appears in many everyday situations, such as a cable holding a sign or a string lifting an object. Understanding tension helps students connect force diagrams to real motion.

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 mass and weight are different in physics. This K12 science video explains mass as matter and weight as the force of gravity on an object.

How Mass Differs from Weight | JoVE K12

JoVE Core Mechanical Engineering offers concise, easy-to-understand animated videos covering key topics such as equilibrium, forces, truss analysis, and structural mechanics. Explore their real-world applications, and witness these concepts in action through scientist-led experiments.

mechanical engineering

How Mass Differs from Weight

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