Name: si and customary measurement systems
Uploaded: 2023-09-22T11:49:19.000Z
Duration: 1 min 27 s
Channel: JoVE

長さ、質量、および時間は測定の基本量であり、それらの単位は基本単位と呼ばれます。
基本単位から派生した単位は、派生単位と呼ばれます。
単位系は、国際単位系またはSI単位と米国の慣習単位系に分類できます。
SI単位では、メートル、キログラム、秒が基本単位ですが、米国の慣習単位系では、フィート、ポンド、秒が基本単位です。
たとえば、SI の力の単位はニュートンで、これは派生した単位です。これは、1 キログラムの質量を 1 秒あたり 1 メートルの 2 乗の割合で加速するために必要な力として定義されます。
米国の慣習単位系では、質量の単位は派生単位であるスラッグです。これは、1ポンドの力で作用したときに1フィート/秒に2乗加速される物質の量として定義されます。
変換係数を使用して、1 つのシステムの単位を別のシステムの単位に変換できます。

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	<li>ビール、FP;ジョンストン、ER;マズレック、D.F;クロムウェル、PJおよびセルフ、BP(2019)。エンジニアのためのベクトル力学 \u2012 静力学と動力学。ニューヨーク:マグロウヒル。4 ページと 8</li> ページ
	<li>メリアム、J.L.;Kraige、LGおよびBolton、JN(2020)。エンジニアリングメカニクス \u2012 静力学。ニュージャージー州ホーボーケン:ジョン・ワイリー。7 ページと 8 ページ</li>
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計測単位

Units of Measurement

機械工学は、最も古い工学の一つです。機械や機械システムの設計、分析、製造に関わります。精密で正確な計算を保証するために、計測単位を使用します。これらは物理的な量を表現し比較するための標準システムを提供します。
バビロニアのシステム、ローマのシステム、エジプトのシステム、オリンピアのシステム、イギリスのシステム、インダス川流域のシステムなど、さまざまな有名な歴史的な計測システムがあります。
国際単位系（SI）は、機械工学で使用される計測の普遍的に認識された標準です。これは他のすべての物理的な量を表現するために組み合わせることができるいくつかの基本単位に基づいています。
基本単位から派生した単位は、派生単位として知られています。たとえば、力のSI単位はニュートンであり、これは派生単位です。これは質量が1キログラムの物体を1秒間に1メートル加速させるのに必要な力と定義されています。
世界中でさまざまな計測単位のシステムが使用されています。国際単位系（SI）に加えて、米国慣用単位もよく使用されています。米国慣用単位では、基本単位はフィート、ポンド、秒です。長さの単位はフィート、質量の単位はポンド、時間の単位は秒です。
米国慣用単位系では、質量の単位は「スラグ」と呼ばれる派生単位です。これは、1ポンドの力によって1フィート毎秒の速度で加速される物体の質量と定義されています。
多くの国が米国慣用単位系を使用しているため、さまざまな単位の比較関係も開発されています。たとえば、1メートルは3,280フィートに等しいです。派生単位も規格ごとに異なります。たとえば、SI系は力の単位としてニュートンを使用しますが、米国慣用単位系はポンドを使用します。
計測単位は、機械工学では正確で精密な測定を可能にするために必要です。エンジニアはこれらの単位を使用して機械や機械システムの設計と分析、機械部品にかかる荷重、応力、変形の解析、さらにはさまざまな運転条件下での機械の挙動を予測します。

機械工学は、工学の最も古い分野の1つです。機械と機械の設計、分析、製造を扱っています...

Education

JoVE Core

Mechanical Engineering

機械工学

Unit 1

ユニット1

An Introduction to Statics

静力学入門

KEY TERMS AND CONCEPTS

主要用語と概念

si and customary measurement systems

Mechanical engineering depends on units of measurement for precise and accurate calculations. These units give engineers a standard way to express and compare physical quantities. They are essential when designing and analyzing machines and mechanical systems.

Many historical measurement systems have been used over time. Examples include the Babylonian system, the Roman system, the Egyptian system, the Olympian system, the British system, and the Indus Valley system. Today, the International System of Units, or SI, is the widely recognized standard used in mechanical engineering.

The SI system is built from base units. These base units can be combined to describe other physical quantities, which are called derived units. For example, the SI unit of force is the Newton. One Newton is the force needed to accelerate one kilogram of mass at one meter per second squared.

Another common system is the U.S. Customary System of Units. Its base units are the foot, the pound, and the second. In this system, length is measured in feet, mass is measured in pounds, and time is measured in seconds. The slug is the derived unit used for mass in this system, and it is defined by the amount of matter accelerated by one foot per second squared under a force of one pound.

Because many countries still use the U.S. Customary System, conversion relationships are important. For example, one meter equals 3,280 feet. Derived units also differ between systems. SI uses the Newton for force, while the U.S. Customary System uses the pound. Engineers use these units to estimate loads, stresses, and deformations, and to predict how machines behave under different operating conditions.

SI and Customary Measurement Systems

an introduction to mechanics

Mechanics in Physics and Engineering

Mechanics is a key branch of physics that explains how objects stay at rest or move when forces act on them. It also has major uses in engineering and science. The topic helps students understand everyday motion, machine behavior, and the way many systems work. The recorded history of mechanics begins with Aristotle, who lived from 384 to 322 BC. He linked mechanics with physical theory and looked for a broad universal explanation. Later, Newton defined mechanics as the study of objects at...

basic concept

Fundamental Quantities in Engineering Mechanics

Engineering mechanics begins with four basic quantities: length, time, mass, and force. These ideas help describe how objects move and how they respond to loads. They also support many other engineering fields. Length measures the distance traveled by an object. Engineers describe this distance with coordinates relative to a reference point. Length is also useful for showing the geometry of physical systems. Time measures the succession of an event. A bus traveling from city X to city Y is a...

newton's law of motion

Newton's Laws and Everyday Motion

Newton's laws explain everyday motion and the forces that change it. These three laws describe why objects move, stay still, or speed up. They also show how force and mass affect motion. Newton's first law is the law of inertia. It says an object at rest stays at rest, and an object in motion keeps moving at a constant speed and direction unless an external force acts on it. A sliding box that slows down on its own is a good example. In that case, friction is the net external force that works...

newton's law of gravitational attraction

Gravity Between Masses and Distance

Newton’s law of gravitational attraction describes how gravity acts between two objects. Sir Isaac Newton built this law from empirical evidence and inductive reasoning. He published it in Philosophiae Naturalis Principia Mathematica, or the Principia, on July 5, 1687. The law says that the gravitational force between any two objects depends on their masses and their distance apart. The force is proportional to mass and inversely proportional to the square of the distance between the objects.

units of measurement

Mechanical engineering depends on units of measurement for precise and accurate calculations. These units give engineers a standard way to express and compare physical quantities. They are essential when designing and analyzing machines and mechanical systems. Many historical measurement systems have been used over time. Examples include the Babylonian system, the Roman system, the Egyptian system, the Olympian system, the British system, and the Indus Valley system. Today, the International...

international system of units

SI Units and Metric Prefixes

SI units and metric prefixes provide a standard way to measure size, mass, and time. The International System of Units, or SI system, is used worldwide because it gives scientists a common language for measurement. Its values do not change with location, which helps keep results consistent. The SI system is built on three base units: meter, kilogram, and second. These are the core units for length, mass, and time. The kilogram is the only base unit that already includes a prefix. Prefixes...

numerical calculations

Engineering Notation and Significant Figures

Numerical calculations in engineering depend on clear values, correct units, and careful rounding. Presenting the answer is an important part of engineering practice, so numerically accurate results are preferred. Handheld calculators and computers are often used because they help produce accurate answers. Problems can be solved in several ways. Solving algebraic symbols by hand is common, and the graphical method is often preferred in some cases. Computers are especially useful when many...

accuracy, limits, and approximation

Accuracy and Approximation in Calculations

Accuracy and approximation are important in calculations, especially in engineering. Accuracy means how close a measured value is to the true or actual value. Repeated measurements are often used in engineering mechanics to help make results more precise and accurate. The accuracy of a solution depends on empirical data and the results from different calculations or measurements. A cylindrical container filled with liquid is a simple example. Its volume can be found from the measured...

dimensional analysis

Using Dimensions to Check Physics Equations

Dimensional analysis is a useful way to check physics and engineering equations. It works by writing physical quantities in terms of basic dimensions such as mass, length, and time. Quantities like velocity, acceleration, and force are derived from these basic dimensions. This method helps compare measurements even when the units are different. It also checks whether an equation is dimensionally homogeneous. That means the powers of the fundamental dimensions must match on both sides of the...

problem solving in statics

Statics Problem-Solving Steps for Beams

Statics problem-solving uses a step-by-step method to analyze bodies in equilibrium, especially beams. It is an important part of physics and engineering because the goal is to find practical and accurate answers for real situations. The process usually starts with a physical situation and then turns it into a mathematical model. That model often needs approximations and assumptions. Very small distances can be ignored when they are much smaller than the main dimensions, such as beam width...

key terms and concepts

Explore SI and U.S. Customary units, base and derived units, and how engineers use measurement systems to calculate force, loads, and machine behavior.

SI and Customary Measurement Systems | JoVE K12

JoVE Core 機械工学は、平衡、力、トラス解析、構造力学などの重要なトピックをカバーする簡潔でわかりやすいアニメーション ビデオを提供します。実際のアプリケーションを探索し、科学者主導の実験を通じてこれらのコンセプトが実際に動作しているのを目撃してください。

mechanical engineering

SI and Customary Measurement Systems

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