Name: tracking motion with position and displacement
Uploaded: 2023-09-22T11:49:39.000Z
Duration: 1 min 31 s
Channel: JoVE

オブジェクトの動きを記述するには、その位置を便利な参照フレームに対して相対的に指定する必要があります。オブジェクトの位置と動きを記述する任意の軸のセットは、参照フレームと呼ばれます。
一般に、地球または地球上の静止物体は、参照フレームとして使用されます。たとえば、離陸中の航空機の位置は、地球全体または空港の管制塔に対して記述できます。1次元の動きに沿ったオブジェクトの位置を説明するために、変数xをよく使用します。
ここで、オブジェクトが参照フレームに対して相対的に移動するとします (たとえば、車が建物に対して左に移動すると、車の位置が変わります)。この位置の変化は変位と呼ばれます。
ただし、直線に沿った x の数値は、オブジェクトが配置される可能性のあるオブジェクトの位置を定義します。この線に沿った位置の変化は変位で示され、Δx は変位であり、最終位置から初期位置を差し引いて計算されます。これは方向を示すためベクトル量であり、正の方向の選択に応じて、正または負のいずれかになります。

位置と変位

物体の位置は、特定の時点における便利な参照フレームに対する相対的な位置を定義します。 参照フレームは、物体の位置と動作を記述するための任意の軸のセットです。 地球は参照フレームとしてよく使用され、地球上の静止物体に関連して物体の位置を説明することがよくあります。 たとえば、ロケットの打ち上げは、地球全体に対するロケットの位置という観点から説明できます。 一方、サイクリストの位置は、通過する建物との関係で自分がどこにいるかという観点から説明できます。 他の場合には、静止しておらず、地球に対して動いている参照フレームを使用します。 たとえば、飛行機内の人の位置を記述するには、参照フレームとして地球ではなく飛行機を使用します。 一次元の動きをしている物体の位置を記述するには、変数 x をよく使用します。

物体が参照フレームに対して移動すると、物体の位置が変わります。 たとえば、教授がホワイトボードに対して右に移動すると、教授の位置が変わります。 この位置の変化を変位と呼ばれます。 「変位」という言葉は、物体が移動した、または位置が移動したことを意味します。 位置は物体が存在する直線上のxの値ですが、変位はこの直線に沿った位置の変化を与えます。 変位は方向を持つため、ベクトル量であり、正として選択された方向に応じて正または負のいずれかになります。

また、動作の解析には多くの変位を組み込むことができます。 たとえば、右を正とすると、物体は右に 2 m、次に左に 4 m移動した場合、個々の変位はそれぞれ 2 m と 4 m になります。 変位は x で示され、位置の変化を表します。 常に最終位置から初期位置を減算することで変位を解決します。

このテキストは、<a href="https://openstax.org/books/university-physics-volume-1/pages/3-1-position-displacement-and-average-velocity">Openstax University Physics Volume 1, Section 3.1: Position, Displacement, and Average Velocity</a> から改変されたものです。.

オブジェクトの位置は、特定の時間における便利な参照フレームに対する相対的な位置を定義します。参照フレームは任意の...

Education

JoVE Core

Mechanical Engineering

機械工学

Unit 1

ユニット1

Physics Basics

物理学の基礎

KEY TERMS AND CONCEPTS

主要用語と概念

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.

Tracking Motion with Position and Displacement

tracking-motion-with-position-and-displacement

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

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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

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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

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

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acceleration due to gravity on earth

Free-Fall Acceleration on Earth

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tension

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gravitational force

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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 position and displacement describe straight-line motion. Explore the origin, change in position, and direction in a clear high school science format.

Tracking Motion with Position and Displacement | JoVE K12

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mechanical engineering

Tracking Motion with Position and Displacement

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