Name: mechanics in physics and engineering
Uploaded: 2023-09-22T11:49:18.000Z
Duration: 1 min 28 s
Channel: JoVE

K12 Standards

Arizona Science Standards

High School

Physical Science

HS.P3

HS.P3U2.7

An Introduction to Mechanics

Механика — раздел физической науки, изучающий состояние объекта в покое или в движении под действием сил.
Обычно его классифицируют как механику твердого тела, механику деформируемого тела и механику жидкости.
Механика твердого тела изучает те объекты, в которых деформация под действием сил пренебрежимо мала.
Его можно разветвлять на статику и динамику. Статика имеет дело с состоянием объектов, находящихся в состоянии покоя, в то время как динамика имеет дело с объектами в движении.
Динамика далее делится на кинематику и кинетику, где силами, ответственными за движение, пренебрегают и учитывают, соответственно.
Механика деформируемого тела изучает деформацию объекта под действием сил.
Изучение движения и сил жидкостей называется механикой жидкости. Далее он классифицируется на сжимаемые и несжимаемые жидкости.
Проектирование и анализ таких конструкций, как здания, листовые рессоры в автомобилях, крюки кранов, пневматические гвоздезабивные пистолеты, гидравлические тормозные системы и промышленные роботы, основаны на принципах механики.

<ol>
	<li>Хиббелер, Р.К. (2016). Инженерная механика \u2012 Статика и динамика. Хобокен, Нью-Джерси: Пирсон Прентис Холл. С. 3 \u2012 4</li>
	<li>Бир, Ф..; Джонстон, Э.Р.; Мазурек, Д.Ф; Кромвель,.Д. и Селф, Б.. (2019). Векторная механика для инженеров \u2012 Статика и динамика. Нью-Йорк: Макгроу-Хилл. С. 2 \u2012 3</li>
	<li>Мериам, Дж.Л.; Крайге, Л.Г. и Болтон, Д.Н. (2020). Инженерная механика \u2012 Статика. Хобокен, Нью-Джерси: Джон Уайли. С. 1 \u2012 2</li>
</ol>

Введение в механику

Люди на протяжении веков создавали корабли, убежища, пирамиды, оружие, сельскохозяйственное оборудование и многое другое, не записывая процесс или теорию позади них. Было бы сложно задокументировать эволюцию механики от её возникновения до настоящего времени.

Согласно записям, история механики начинается с Аристотеля (384-322 гг. до н.э.). Он связывал механику с физической теорией, стремясь к универсальному синтезу.

Ньютон определил механику как раздел физической науки, изучающий состояние объекта в покое или движении под воздействием сил. Механика является фундаментальной областью физики со значительными применениями в различных отраслях инженерии и науки. Изучение механики необходимо для понимания движения повседневных объектов, поведения машин и устройств, а также функционирования различных систем.

Механика твёрдого тела — это раздел механики, который занимается объектами, в которых деформация пренебрежима при действии сил. Механику твёрдого тела можно разделить на статику и динамику. Статика занимается состоянием покоящихся объектов, тогда как динамика занимается объектами в движении. Динамика дальше делится на кинематику и кинетику, при этом первая не учитывает силы, ответственные за движение, а вторая их учитывает.

Механика деформируемого тела, с другой стороны, фокусируется на деформации объекта при действии сил. Понимание поведения материалов, таких как использованные в строительстве или производстве, а также проектирование и анализ различных структур является ключевым.

Гидромеханика — это изучение движения и сил жидкостей. Это обширная область, которая классифицируется на сжимаемые и несжимаемые жидкости, в зависимости от их поведения. Гидромеханика имеет много практических применений и используется при проектировании и анализе различных систем, таких как гидравлические или пневматические системы, системы транспортировки жидкостей и оборудование для химической переработки.

Множество структур и машин проектируются и анализируются на основе принципов механики. Например, проектирование зданий, мостов и других конструкций зависит от принципов механики для оценки прочности материалов, силы притяжения и движения Земли. Принципы механики также используются при проектировании компонентов автомобилей, таких как листовые пружины и гидравлические тормозные системы, крюки для кранов, промышленные роботы и пневматические гвоздезабивные пистолеты.

Люди создавали корабли, убежища, пирамиды, оружие, сельскохозяйственное оборудование и многое другое, не записывая процесс или теорию, стоящую за ними...

Education

JoVE Core

Mechanical Engineering

Машиностроение

Unit 1

Раздел 1

An Introduction to Statics

Введение в статику

KEY TERMS AND CONCEPTS

ОСНОВНЫЕ ТЕРМИНЫ И ПОНЯТИЯ

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 rest or in motion under the action of forces.

Rigid body mechanics deals with objects that do not deform much when forces act on them. This area is divided into statics and dynamics. Statics studies objects at rest, while dynamics studies objects in motion.

Dynamics is further divided into kinematics and kinetics. Kinematics describes motion without focusing on the forces that cause it. Kinetics includes those forces and explains how they affect motion.

Deformable body mechanics focuses on how objects change shape under force. This is important for understanding materials used in construction and manufacturing. It also helps in the design and analysis of structures.

Fluid mechanics studies the motion of fluids and the forces within them. It is often divided into compressible and incompressible fluids, based on how the fluid behaves. This field is used in hydraulic and pneumatic systems, fluid transportation, and chemical processing equipment.

Principles of mechanics guide the design of many structures and machines. Buildings and bridges are analyzed for material strength, gravity, and earth movement. The same ideas also apply to automobile leaf springs, hydraulic braking systems, crane hooks, industrial robots, and pneumatic nail guns.

Mechanics in Physics and Engineering

an introduction to mechanics

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

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...

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

Learn how mechanics explains motion, forces, statics, dynamics, fluids, and material behavior, with real-world examples in structures and machines.

Mechanics in Physics and Engineering | 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

Position and Displacement

The position of an object defines its location relative to a convenient frame of reference at any particular time. A frame of reference is an arbitrary ...

Average Velocity

To calculate the other physical quantities in kinematics, we must introduce the time variable. The time variable allows us not only to state the position ...

Average Acceleration

The importance of understanding acceleration spans our day-to-day experiences, as well as the vast reaches of outer space and the tiny world of subatomic ...

Instantaneous Acceleration

Acceleration is in the direction of the change in velocity, but it is not always in the direction of motion. When an object slows down, its acceleration ...

velocity-and-position-by-graphical-method

Velocity and Position by Graphical Method

Velocity and position can be calculated from the known function of acceleration as a function of time. The total area under the acceleration-time graph ...

Kinematic Equations - I

When an object moves with constant acceleration, the velocity of the object changes at a constant rate throughout the motion. The kinematic equations of ...

Kinematic Equations: Problem Solving

When analyzing one-dimensional motion with constant acceleration, the problem-solving strategy involves identifying the known quantities and choosing the ...

Force

Forces affect every moment of our life. Our bodies are held to the Earth by force, and they are held together by the forces of charged particles. When we ...

Mass and Weight

Mass and weight are often used interchangeably in everyday conversation. For example,&#160; medical records often show our weight in kilograms, but never ...

Newton's Laws of Motion

Source: Andrew Duffy, PhD, Department of Physics, Boston University, Boston, MA
This experiment examines at various situations involving two interacting ...

Newton's First Law: Introduction

Motion draws our attention. Motion itself can be beautiful, causing us to marvel at the forces needed to create spectacular sights, such as that of a ...

first-law-particles-in-one-dimensional-equilibrium

First Law: Particles in One-dimensional Equilibrium

Newton&#39;s first law of motion states that a body at rest remains at rest, or if in motion, remains in motion at constant velocity, unless acted on by a ...

Newton's Second Law

Newton&#39;s second law is closely related to his first law of motion. It mathematically gives the cause-and-effect relationship between force and changes ...

Force and Acceleration

Source: Nicholas Timmons,&#160;Asantha Cooray, PhD, Department of Physics &#38; Astronomy, School of Physical Sciences, University of California, Irvine, ...

Second Law: Motion under Same Force

Newton&#39;s laws can be applied to bodies at rest and bodies in motion. Newton&#39;s first law is applied to bodies in equilibrium, whereas the second ...

Newton's Third Law: Introduction

Whenever one body exerts a force on a second body, the first body experiences a force equal in magnitude and opposite in direction, to the force that it ...

Drawing Free-body Diagrams: Rules

The first step in describing and analyzing most phenomena in physics involves the careful drawing of a free-body diagram. Free-body diagrams are useful in ...

Free Body Diagrams: Examples

Solving problems that involve forces is easy using free-body diagrams. A free-body diagram is a sketch showing all the external forces that are acting on ...

Equilibrium and Free-body Diagrams

Source: Ketron Mitchell-Wynne, PhD, Asantha Cooray, PhD, Department of Physics &#38; Astronomy, School of Physical Sciences, University of California, ...

Collect, analyze and interpret data regarding the change in motion of an object or system in one dimension, to construct an explanation using Newton’s Laws.

HS.P3U1.6

Solving Problems in Physics

Problem-solving is the ability to apply general physical principles to specific situations, usually expressed by equations. It is an essential skill in ...

Problem Solving in Statics

Problem-solving in statics is a crucial aspect of engineering and physics that involves resolving issues associated with bodies in a state of equilibrium. ...

Humans have been making ships, shelters, pyramids, weapons, agricultural equipment, and many more items without recording the process or theory behind ...

Introduction to Structures

A structure is defined as a system of interconnected members designed to support or transfer forces and successfully withstand the loads acting on them. ...

Simple Trusses

A truss is a structural framework consisting of slender members connected at joints, designed to support external loads while minimizing material usage ...

Method of Joints

The method of joints is a commonly used technique to analyze the forces in structural trusses. The method is based on the principle of equilibrium, which ...

Rigid Body Equilibrium Problems - I

A rigid body is said to be in static equilibrium when the net force and the net torque acting on the system is equal to zero. To solve for rigid body ...

Stability of structures

Consider two rods connected at point O by a pin and a torsional spring of constant k. The ends of both the rods are pin-connected.
If both the rods are ...

Buckling of Steel Columns

Source:&#160;Roberto Leon, Department of Civil and Environmental Engineering, Virginia Tech, Blacksburg, VA
In the design of civil works, it is important ...

Machines

Machines are complex structures consisting of movable, pin-connected multi-force members that work together to transmit forces. One example of a machine ...

DC Motors

Source: Ali Bazzi, Department of Electrical Engineering, University of Connecticut, Storrs, CT. 
The DC machine operates with DC currents and voltages as ...

Rolling Resistance

When a solid cylinder rolls steadily on a rigid surface, the normal force applied by the surface on the cylinder is perpendicular to the tangent at the ...

Propulsion and Thrust

Source: Alexander S Rattner; Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA
Aircraft, rockets, ...

Rocket Propulsion in Empty Space - I

The driving force for the motion of any vehicle is friction, but in the case of rocket propulsion in space, the friction force is not present. The motion ...

aerodynamic-performance-of-a-model-aircraft-the-dc-6b

Aerodynamic Performance of a Model Aircraft: The DC-6B

Source: Jose Roberto Moreto and Xiaofeng Liu, Department of Aerospace Engineering, San Diego State University, San Diego, CA
The low-speed wind tunnel is ...

airfoil-behavior-pressure-distribution-over-a-clark-y-14-wing

Airfoil Behavior: Pressure Distribution over a Clark Y-14 Wing

Source: David Guo, College of Engineering, Technology, and Aeronautics (CETA), Southern New Hampshire University (SNHU), Manchester, New Hampshire
An ...

Use mathematics and computational thinking to explain how Newton’s laws are used in engineering and technologies to create products to serve human ends.

Mechanics in Physics and Engineering

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