Name: free-body diagrams for force analysis
Uploaded: 2023-09-22T11:49:20.000Z
Duration: 1 min 28 s
Channel: JoVE

K12 Standards

Next Generation Science Standards

High School

Physical Science

motion-and-stability-forces-and-interactions

Motion and Stability: Forces and Interactions

HS-PS2-3

Free-body Diagram

입자에 작용하는 모든 힘의 시각적 표현을 자유체 다이어그램 또는 힘 다이어그램이라고 합니다. 복잡한 문제를 단순한 표현으로 변환합니다.
자유물체 다이어그램에서 화살표의 방향은 힘의 방향을 나타내고 화살표의 길이는 힘의 크기를 나타냅니다.
두 개의 판지 상자가 쌓여 있는 고정식 트롤리를 생각해 보십시오.
여기서, 두 개의 관심 시스템, 즉 상자 1과 상자 2는 고립된 시스템으로 가정할 수 있으며, 간단한 윤곽선 또는 점 형태의 자유물체 다이어그램을 사용하여 나타낼 수 있습니다.
상자 1에 작용하는 힘은 무게를 정의하는 중력과 상자 2로 인한 역균형 법선력입니다.
유사하게, 상자 2에 가해지는 힘은 자체 무게, 트롤리로 인한 수직력 및 상자 1의 무게입니다.
자유물체 다이어그램은 특정 물리적 상황에서 역학의 추상적인 수학 방정식으로의 전환으로 문제 해결 과정에서 필수적인 역할을 합니다.

<ol>
	<li>히벨러, R.C. (2016). Engineering Mechanics \u2012 정역학 및 동역학. 뉴저지 호보켄: 피어슨 프렌티스 홀. 88쪽</li>
	<li>맥주, F.P.; 존스턴, ER; 마주렉, D.F; 크롬웰, PJ 및 셀프, BP (2019). 엔지니어를 위한 벡터 역학 \u2012 Statics and Dynamics. 뉴욕 : McGraw-Hill. 쪽 170-171</li>
</ol>

자유물체도

역학에서 물체의 운동을 이해하는 것은 필수적인데, 이 문제를 해결하는 데 도움을 주는 도구 중 하나가 자유 물체도입니다. 이것은 물체에 작용하는 모든 힘을 간결하게 표현하는 간단하지만 강력한 그래픽 표현입니다. 자유 물체도는 정지해 있거나 움직이는 물체를 나타낼 수 있으며, 역학에서 물체의 운동 원인을 설명하는 데 사용됩니다.
자유 물체도는 복잡한 문제를 간단한 표현으로 변환시켜 물체에 작용하는 필수적인 힘을 쉽게 이해할 수 있게 하여 수학 방정식을 도출할 수 있도록 합니다. 많은 경우 자유 물체도를 사용하지 않고 방정식을 유도하기는 매우 복잡할 것입니다. 자유 물체도를 만들려면 먼저 검사 중인 물체나 시스템을 선택하고 주변으로부터 분리한 다음 점이나 간단한 윤곽선으로 그립니다. 다음으로 관심 있는 물체나 시스템에 작용하는 모든 필수적인 외력을 화살표로 나타냅니다. 화살표의 방향은 힘의 방향을 나타내고 화살표의 길이는 힘의 크기를 나타냅니다. 자유 물체도에서 속도와 가속도는 표현되지 않지만 물체에 가해지는 힘으로 추론할 수 있습니다. 
자유 물체도로 나타낼 수 있는 일반적인 유형의 힘에는 무게, 수직력, 장력, 마찰력, 가해진 힘 등이 있습니다. 무게는 물체에 작용하는 중력을 나타내며, 일반적으로 아래를 가리키는 화살표로 표시됩니다. 수직력은 두 물체가 접촉했을 때 두 물체 사이의 힘이며, 이 힘은 물체의 무게와 반대 방향으로 작용합니다. 일반적으로 장력은 물체에서 멀리 떨어진 힘의 방향을 가리키는 화살표로 표시되며, 마찰력은 표면 사이의 미끄러짐에 저항하는 힘입니다. 마지막으로 가해진 힘은 밀거나 당기는 힘과 같은 외부 작용제가 물체에 가하는 힘을 나타냅니다. 가해진 힘은 힘의 방향을 가리키는 화살표로 표시됩니다. 
두 장의 판지 상자가 쌓여 있는 정지해 있는 전차를 생각해 보자. 관심 있는 두 시스템, 즉 상자 1과 상자 2는 고립시스템이라고 가정할 수 있고 자유 물체도로 나타낼 수 있다. 상자 1에 작용하는 힘은 무게를 정의하는 중력과 상자 2에 의한 역균형 수직력입니다. 마찬가지로 상자 2에 작용하는 힘은 무게, 전차에 의한 수직력, 상자 1의 무게입니다.

역학에서는 물체의 움직임을 이해하는 것이 필수적이며, 이 문제를 해결하는 데 도움이 되는 도구 중 하나는 자유물체 다이어그램입니다. 그것은 간단하지만 ...

Education

교육

JoVE Core

Mechanical Engineering

기계공학

Unit 1

제1단원

Equilibrium of a Particle

입자의 평형

KEY TERMS AND CONCEPTS

주요 용어 및 개념

free-body diagrams for force analysis

Free-body diagrams help analyze the forces acting on an object in mechanics. They give a simple picture of a stationary or moving object and show why it moves the way it does. By turning a complex situation into a clear sketch, they make it easier to write the equation needed to solve the problem.

To draw a free-body diagram, first choose the object or system you want to study. Then isolate it from its surroundings and draw it as a dot or a simple outline. Add arrows for every important external force. The direction of each arrow shows the direction of the force, and the length shows its size.

A free-body diagram does not show velocity or acceleration. Those quantities are not drawn on the diagram, but they can be inferred from the forces acting on the object. Common forces include weight, normal force, tension, friction, and applied force. Weight is the force of gravity and is usually shown with an arrow pointing downward.

Normal force is the contact force between two objects touching each other. It acts in the direction opposite to the object's weight in many situations. Tension is usually drawn as an arrow away from the object and along the direction of the pull. Friction resists sliding between surfaces. Applied force is an outside push or pull, and it is shown with an arrow in the direction of that force.

A stationary trolley with two cardboard boxes stacked on it gives a clear example. Box one and box two can each be treated as separate isolated systems and shown with their own free-body diagrams. For box one, the forces are gravitational force and the balancing normal force from box two. For box two, the forces are its weight, the normal force from the trolley, and the weight of box one.

Free-Body Diagrams for Force Analysis

equilibrium conditions for a particle

Balanced Forces and Torque in Equilibrium

Equilibrium depends on balanced forces and balanced torque. An object in equilibrium is either at rest or moving with a constant velocity. These two cases are called static equilibrium and dynamic equilibrium. Static equilibrium means the object is not moving. Dynamic equilibrium means the object is moving, but its velocity stays constant. In both cases, the forces acting on the object must balance each other. Different forces can add, subtract, or cancel each other out. When the vector sum...

free-body diagram

Free-body diagrams help analyze the forces acting on an object in mechanics. They give a simple picture of a stationary or moving object and show why it moves the way it does. By turning a complex situation into a clear sketch, they make it easier to write the equation needed to solve the problem. To draw a free-body diagram, first choose the object or system you want to study. Then isolate it from its surroundings and draw it as a dot or a simple outline. Add arrows for every important...

steps for free-body diagram

Free-Body Diagram for Two-Block Motion

A free-body diagram helps analyze two-block motion in mechanics. It shows the forces acting on a system so the net force can be found and the acceleration can be calculated. The example in this lesson uses two blocks linked by a massless string over a frictionless pulley. Block 1 moves across a table while block 2 falls under gravity. The two blocks are treated as one isolated system. External forces are then identified and drawn as vector arrows on the diagram. For block 1, the forces...

free-body diagrams: problem solving

Free-Body Diagrams on Inclined Planes

Free-body diagrams help show the forces acting on an object on an inclined plane. A free-body diagram is a simple drawing that focuses only on the object or system being studied. It leaves out extra details so the force problem is easier to analyze and solve. For an example, a 10 kg block is released on a ramp that is 30° to the horizontal. The coefficient of friction is 0.2. The diagram for this block includes the weight from gravity, the normal force, and the frictional force. These are the...

coplanar forces

Resolving Coplanar Force Components

Coplanar forces act on an object in the same plane. To analyze this kind of system, each force is resolved into x and y components using Cartesian vector form and vector algebra. This makes it possible to test whether the object is in equilibrium. A coplanar system is in equilibrium when the resultant force is zero. That means the sum of the forces in each direction must also be zero. If the forces do not balance, the object is not in equilibrium and will accelerate in the direction of the net...

categories of equilibrium

Types of Equilibrium in Forces

Equilibrium in physics describes how forces act on a body so it stays still or moves at a constant speed. In two-dimensional force systems, equilibrium can be grouped into several categories based on how the forces are arranged. Collinear equilibrium is the simplest case. The forces act along one straight line, so only one force equation is needed in the direction of those forces. The other equations are already satisfied. Coplanar concurrent equilibrium is another category. In this case, all...

key terms and concepts

Learn how free-body diagrams show weight, normal force, tension, friction, and applied force. See how isolating an object simplifies force analysis in mechanics.

Free-Body Diagrams for Force Analysis | 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.

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HS-PS2-6

Free-Body Diagrams for Force Analysis

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