Name: why motion seems different in accelerating frames
Uploaded: 2023-04-30T10:54:29.000Z
Duration: 1 min 27 s
Channel: JoVE

K12 Standards

Pennsylvania State Academic Standards

9-12

Physical Science

Forces and Interactions

3.2.9-12.J

Non-inertial Frames of Reference

뉴턴의 법칙이 적용되는 기준틀은 관성틀(inertial frames)로 알려져 있다는 것을 기억하십시오. 그러나 비관성 기준계(non-inertial reference frames)라고 하는 뉴턴의 법칙을 무시하는 기준계가 있습니다.
비관성 프레임은 관성 프레임에 비해 가속되거나 감속됩니다.
예를 들어, 비행기가 이륙할 때 승객은 비행기의 가속도에 반대되는 역력을 느낍니다. 이것은 물체가 알짜 외력의 방향으로 가속된다는 뉴턴의 두 번째 법칙을 위반합니다.
비관성 프레임에서는 물리적 기원이 없는 관성 또는 가상의 힘이 물체의 움직임을 설명하는 데 필요합니다. 따라서 역학에서는 관성 프레임을 사용하는 것이 더 편리합니다.
이상적으로, 지구에 고정된 기준계는 지구의 회전과 자전으로 인해 비관성입니다. 그러나 지구의 자전으로 인한 힘은 작은 기계적 움직임에서는 무시할 수 있지만 바람 패턴과 같은 대규모 운동에는 영향을 미칩니다.
이 프레임의 가상의 힘은 북반구에서는 시계 방향으로, 남반구에서는 시계 반대 방향으로 바람을 편향시킵니다.

비관성 참조 프레임

관성계를 기준으로 가속 또는 감속하는 기준계는 비관성계입니다. 이를 이해하는 데 도움이 되도록 비행기 이륙, 자동차 코너링, 회전목마 타기, 열대 저기압의 원운동 모두의 공통점을 생각해 보십시오. 이 모든 시스템은 지구를 기준으로 가속, 감속 또는 회전하고 있습니다. 따라서 이것은 모두 비관성 프레임입니다. 이러한 모든 시스템은 관찰자의 기준 프레임이 가속되거나 회전하기 때문에 단지 운동에서 발생하는 것처럼 보이는 관성력을 나타냅니다. 우리는 사용된 참조 프레임을 검토함으로써 이러한 관점을 조정할 수 있습니다. 물리학자는 분석 중인 상황에 가장 편리한 참조 프레임을 선택합니다. 물리학자들은 평소와 같이 관성력과 뉴턴의 제2법칙을 포함하는 데 아무런 문제가 없습니다. 마찬가지로, 도움이 될 때는 비관성(가속) 참조 프레임이 사용됩니다. 예를 들어, 빛의 속도에 가까운 속도로 이동하는 우주선 안의 우주비행사의 움직임을 논의할 때 다양한 기준틀을 고려해야 합니다. 이는 특수 상대성 이론에 적용되기 때문입니다.

지구는 회전으로 인해 발생하는 영향에 대해 거의 또는 전혀 걱정하지 않고 관성 기준계로 사용할 수 있습니다. 그러나 예를 들어 기상 시스템의 순환과 같은 효과는 존재합니다. 북극 위에서 보면 지구는 시계 반대 방향으로 회전하며 지구 북반구의 모든 움직임은 오른쪽으로 코리올리 힘을 경험합니다. 남반구에서는 반대의 현상이 일어나며 힘이 왼쪽으로 가해집니다. 지구의 각속도가 작기 때문에 코리올리 힘은 일반적으로 무시할 수 있지만 바람 패턴과 같은 대규모 운동에는 상당한 영향을 미칩니다. 코리올리 힘은 북반구의 허리케인을 시계 반대 방향으로 회전시키는 반면, 남반구의 열대 저기압은 시계 방향으로 회전하게 합니다.

열대 저기압의 회전과 회전목마에 있는 공의 경로는 관성과 아래 시스템의 회전으로 잘 설명될 수 있습니다. 비관성 프레임을 사용하는 경우 곡선 경로를 설명하기 위해 코리올리 힘과 같은 관성력을 고안해야 합니다. 이러한 관성력의 식별 가능한 물리적 원인은 없습니다. 관성 프레임을 사용하는 경우 관성은 경로를 설명하며 모든 힘에 대해 식별 가능한 소스가 있습니다. 자연을 설명하기 위해 두 가지 관점 중 하나를 사용할 수 있지만 모든 힘에는 기원과 설명이 있으므로 관성계의 관점이 더 간단합니다.

이 텍스트는 <a href="https://openstax.org/books/university-physics-volume-1/pages/5-6-common-forces"> 에서 수정되었습니다. Openstax, 대학 물리학 1권, 섹션 5.6: 공통 힘</a> 및<a href="https://openstax.org/books/university-physics-volume -1/pages/6-3-centripetal-force"> 섹션 6.3: 구심력.</a>

관성 프레임에 비해 가속 또는 감속하는 참조 프레임은 비관성 프레임입니다. 이것을 이해하는 데 도움이 되도록 에서 이륙하는 것이 무엇인지 고려하십시오.

Education

교육

JoVE Core

Physics

물리학

Unit 1

제1단원

Newton's Laws of Motion

뉴턴의 운동 법칙

KEY TERMS AND CONCEPTS

주요 용어 및 개념

why motion seems different in accelerating frames

A non-inertial frame of reference is a frame that accelerates, decelerates, or rotates relative to an inertial frame. In these frames, motion can look unusual because the observer is moving with the system. That is why an airplane taking off, a car turning a corner, a merry-go-round, and a tropical cyclone can all be examples of non-inertial motion.

These situations can show inertial forces, which seem to appear because the frame itself is accelerating or rotating. The force does not come from a physical source in the usual sense. Instead, it is tied to the observer’s frame of reference.

Physicists choose the reference frame that is most useful for the problem being studied. They can use inertial frames and apply Newton’s second law in the usual way. They can also use non-inertial frames when that makes the description easier.

Different frames of reference matter in special cases, such as an astronaut in a spacecraft moving near the speed of light. This is important in the special theory of relativity. In many problems, the Earth is used as an inertial frame because its rotation causes little trouble.

Even so, Earth’s rotation does affect some motions. Viewed from above the North Pole, Earth rotates counterclockwise. Motion in the Northern Hemisphere then experiences a Coriolis force to the right, while the Southern Hemisphere experiences a force to the left.

Because Earth’s angular velocity is small, the Coriolis force is usually negligible. It still has major effects on large-scale motion, such as wind patterns. It helps explain why hurricanes in the Northern Hemisphere rotate counterclockwise and why tropical cyclones in the Southern Hemisphere rotate clockwise.

The path of a ball on a merry-go-round and the motion of a tropical cyclone can also be explained by inertia and by the rotation of the system underneath. When a non-inertial frame is used, inertial forces such as the Coriolis force must be added to explain the curved path. When an inertial frame is used, inertia explains the motion, and every force has a clear source. Both views can describe nature, but the inertial frame is usually simpler.

Why Motion Seems Different in Accelerating Frames

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force

Understanding Force in Motion

Force is a push or pull that acts on an object. It has both magnitude and direction, so force is a vector quantity. In everyday life, force appears when we open a door, walk down a street, lift a fork, or touch a baby's face. Forces also shape matter at the smallest scales. The atoms in our bodies are held together by electrical forces. The nucleus of an atom is held together by nuclear force, which is the strongest force known to us. The study of motion is called kinematics. Kinematics...

types of forces

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newton's first law: introduction

Newton's First Law and Inertia

Newton's first law of motion explains inertia and how forces change motion. Motion can be striking to observe, from a dolphin jumping from water to a bird in flight or a satellite moving in orbit. The study of motion is kinematics, which describes velocity and acceleration. Dynamics goes further by examining the forces that affect moving objects and systems. Newton's laws of motion are the foundation of dynamics. They are simple in form, but they describe a wide range of natural behavior.

newton's first law: application

Newton's First Law and Friction

Newton's first law explains why friction changes an object's motion. It says that an object at rest stays at rest, and an object in motion keeps moving unless a net external force acts on it. A net external force is the overall force from outside the object that causes a change in velocity, meaning a change in speed or direction. This idea gives a cause-and-effect reason for motion, rather than just describing what we see. Galileo first developed the idea behind the first law of motion, and...

internal and external forces

External Forces and Motion Changes

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newton's second law

Force, Mass, and Acceleration

Newton's second law connects net force, mass, and acceleration. It explains how an object's motion changes when external forces act on it. The law gives a clear cause-and-effect link that can be used to make calculations. All external forces on a system are added together to find the net force, or F net. A larger net external force produces a larger acceleration. The acceleration points in the same direction as the net force. Mass also affects the result. A larger mass means more inertia, so...

mass and weight

Weight Changes, Mass Stays Constant

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weightlessness

Weightlessness in Free Fall

Weightlessness happens when contact forces disappear, even though gravity is still present. In physics, an object in free fall has only gravity acting on it. If the net external force on the object is its weight, the object is accelerating toward the center of the Earth. Galileo showed that, without air resistance, all objects fall with the same acceleration g. On Earth, falling objects are never truly in free fall because air always pushes upward with some resistance force. That is why real...

apparent weight

Scale Readings in Motion and Water

Scale readings can change when an object is moving or submerged in water. The force we call true weight is the gravitational force acting on an object. When motion or fluid forces are present, the reading can differ from that true weight. In water, this changed reading is called apparent weight, and it equals true weight minus the buoyant force. A bathroom scale in an elevator shows how this works. At rest, the scale reads the force the person pushes downward on it. The only forces on the...

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newton's third law: introduction

Newton's Third Law in Force Pairs

Newton's third law explains how force pairs work in motion and interactions. When one body exerts a force on a second body, the first body experiences a force that is equal in magnitude and opposite in direction. A simple example is a person pushing on a wall. The wall pushes back on the person with an equal and opposite force. This is why Newton's third law is often described as action and reaction, where the action is the force exerted and the reaction is the force experienced afterward. <br...

newton's third law: examples

Newton's Third Law in Motion

Newton's third law explains how forces come in pairs during motion. It says that every action has an equal and opposite reaction. In these examples, the two forces act on different systems, so they do not cancel each other out. A swimmer pushing off the side of a pool shows this clearly. The swimmer pushes against the wall with their feet and then accelerates in the opposite direction. The wall pushes back with an equal and opposite force. If the swimmer is the system of interest, the wall's...

drawing free-body diagrams: rules

Free-Body Diagrams for Newton’s Laws

Free-body diagrams help students map the forces acting on an object in physics. They are used often when studying and applying Newton’s laws of motion. A clear diagram makes it easier to analyze a system before solving for motion. Start by drawing the object under consideration. If the object is treated like a particle, show it as a point and place that point at the origin of an x-y coordinate system. Then add every force that acts on the object as a vector. Do not include the net force on the...

free body diagrams: examples

Free Body Diagram Force Examples

Free body diagrams show the external forces acting on an object or system. The object is drawn as a single isolated point, or free body, so the forces are easier to analyze. Only forces that come from outside the object or system are included. These forces are shown as vectors pointing away from the free body. A person sitting on a chair is a simple example. The free-body diagram has two forces. The chair exerts an upward normal force, and gravity pulls downward with the weight. A rocket sled...

inertial frames of reference

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non-inertial frames of reference

A non-inertial frame of reference is a frame that accelerates, decelerates, or rotates relative to an inertial frame. In these frames, motion can look unusual because the observer is moving with the system. That is why an airplane taking off, a car turning a corner, a merry-go-round, and a tropical cyclone can all be examples of non-inertial motion. These situations can show inertial forces, which seem to appear because the frame itself is accelerating or rotating. The force does not come from...

centrifugal force

Rotating Frames and Pseudo Forces

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key terms and concepts

Explore how accelerating, decelerating, and rotating frames change the way motion looks, from cars and merry-go-rounds to Coriolis force and hurricanes.

Why Motion Seems Different in Accelerating Frames | JoVE K12

physics

JoVE Core Physics introduces the theory and application of fundamental physics topics, including kinematics, dynamics, fluid mechanics, statics, waves, and acoustics, with concise and easy-to-understand animated videos. Additionally, the scientist-in-action videos demonstrate the application of related concepts in classical and original research experiments performed in today's laboratories worldwide.

Louisiana Student Standards for Science

High School

motion-and-stability-forces-and-interactions

Motion And Stability: Forces And Interactions

HS-PS2-2

HS-PS2-3

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

Forces And Motion

Motion

Tennessee Academic Standards

Motion and Stability: Forces and Interactions

PHYS.PS2.14

Virginia  Standards of Learning

HIgh School

PS.8

PS.8.b

PH.3

PH.3.a

Next Generation Science Standards

Florida Department of Education

SC.912.P.12

SC.912.P.12.3

SC.912.P.12.8

SC.912.P.12.9

Texas Essential Knowledge and Skills

PHYS.5

PHYS.5.C

new-york-state-science-learning-standards

New York State Science Learning Standards

HS. Forces and Interactions

HS-PS2-1.

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Second Law: Motion under Same Force

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Second Law: Motion under Same Acceleration

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3.2.9-12.I

Inertial Frames of Reference

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3.2.9-12.K

Gravitation

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Newton's Law of Gravitation

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Coulomb's Law

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The Principle of Superposition and the Gravitational Field

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Electric Field

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Magnetic Fields

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Electromagnetic Fields

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Students who demonstrate understanding can use mathematical representations of Newton's Law of Gravitation and Coulomb's Law to describe and predict the gravitational and electrostatic forces between objects. Clarifying Statement: Emphasis is on both quantitative and conceptual descriptions of gravitational and electric fields. Assessment Boundry: Assessment is limited to systems with two objects.

3.2.9-12.L

Energy Transfer in Chemical Reactions

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Batteries and Fuel Cells

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Students who demonstrate understanding can plan and conduct an investigation to provide evidence that an electric current can produce a magnetic field and that a changing magnetic field can produce an electric current. Clarifying Statement: N/A Assessment Boundry: Assessment is limited to designing and conducting investigations with provided materials and tools.

3.2.9-12.M

Why Motion Seems Different in Accelerating Frames

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