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Prepared by: MYRINE YSOBELLE S. SIOCO, REE, RME, LPT ENMECH 1 – ENGINEERING MECHANICS
CAMARINES NORTE STATE COLLEGE
F. Pimentel Avenue, Brgy. 2, Daet, Camarines Norte
COLLEGE OF ENGINEERING
MODULE 1: INTRODUCTION TO MECHANICS
OUTLINE OF LEARNING TOPICS TIME ALLOTMENT: 3 HOURS
Introduction to Mechanics 1.1 Introduction 1.2 Fundamental Concepts and Axioms 1.3 Units and Dimensions 1.4 Scalar and Vector Quantities 1.5 Introduction to Free-Body Diagram INTENDED LEARNING OUTCOMES: By the end of the module, you will:
- develop a solid understanding of fundamental concepts in mechanics such as rigid body, mass, and force;
- describe different system of units;
- understand how to convert from one system unit to another; and
- define physical quantities such as scalar and vector. 1.1 INTRODUCTION Engineering mechanics is a fundamental discipline in the field of engineering that plays a crucial role in the design, analysis, and optimization of various mechanical systems. This branch of engineering focuses on understanding the behavior of objects under various forces and conditions, providing engineers with the necessary tools to predict and control the response of structures, machines, and other mechanical systems. The study of engineering mechanics primarily involves the analysis of forces and their effects on materials and structures. By understanding the principles of statics, dynamics, mechanics of materials, and fluid mechanics, engineers can address a wide range of challenges in the design and development of mechanical systems, ensuring their safety, functionality, and efficiency. Statics , a sub-discipline of engineering mechanics, deals with the analysis of equilibrium conditions in systems subjected to external forces. It helps engineers determine the forces acting on structures, such as bridges, buildings, and other load-bearing elements, ensuring their stability and preventing failure. Dynamic s , another sub-discipline, focuses on the motion of objects and the forces that cause or are affected by this motion. Engineers use the principles of dynamics to design and analyze systems with moving parts, such as automobiles, aircraft, and machinery, ensuring optimal performance and safety. Mechanics of materials , also known as solid mechanics, investigates the behavior of materials under various types of loading, such as tension, compression, bending, and torsion. This knowledge enables engineers to select appropriate materials for specific applications, design structures to withstand expected loads, and predict potential failure points.
Prepared by: MYRINE YSOBELLE S. SIOCO, REE, RME, LPT ENMECH 1 – ENGINEERING MECHANICS
CAMARINES NORTE STATE COLLEGE
F. Pimentel Avenue, Brgy. 2, Daet, Camarines Norte
COLLEGE OF ENGINEERING
Fluid mechanics , a related field, examines the behavior of fluids, both liquids and gases, under various conditions. Engineers use fluid mechanics principles to design hydraulic systems, analyze fluid flow in pipes and channels, and optimize the performance of vehicles and machines that interact with fluids. In conclusion, engineering mechanics is an essential foundation for various engineering disciplines, providing engineers with the knowledge and skills to design, analyze, and optimize mechanical systems. By mastering the fundamental principles of engineering mechanics, engineers can tackle a diverse range of challenges and contribute to advancements in technology, infrastructure, and overall quality of life.
1. 2 FUNDAMENTAL CONCEPTS AND AXIOMS Engineering mechanics is a foundational discipline in engineering that provides a systematic approach to understanding and predicting the behavior of objects subjected to various forces and conditions. To effectively apply engineering mechanics principles in the analysis and design of mechanical systems, it is essential to grasp the fundamental concepts and axioms that govern this field. These foundational ideas form the basis for more advanced topics in statics, dynamics, mechanics of materials, and fluid mechanics. 1. Force : A force is a vector quantity that represents the interaction between two objects, causing or tending to cause a change in their motion. Engineers use forces to model the effects of various loads and constraints on structures and components, ensuring their stability and functionality. 2. Mass and Inertia : Mass is a scalar quantity that represents the amount of matter in an object. Inertia is a property of an object's mass that resists changes in motion. Understanding mass and inertia is crucial for analyzing the effects of forces on objects and predicting their resulting motion. 3. Newton's Laws of Motion : These three fundamental laws form the backbone of classical mechanics and govern the relationship between forces and motion. a. First Law (Law of Inertia) : An object at rest stays at rest, and an object in motion stays in motion with the same speed and direction unless acted upon by an unbalanced force. b. Second Law (F=ma) : The acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. c. Third Law (Action and Reaction ) : For every action, there is an equal and opposite reaction. 4. Equilibriu m : In engineering mechanics, equilibrium refers to a state where the sum of forces and moments acting on a system is zero. Analyzing equilibrium conditions is critical for determining forces and stresses in structures and components. 5. Work, Energy, and Power : Work is the product of force and displacement in the direction of the force. Energy is the capacity to do work, and power is the rate at which work is done. Understanding these concepts is essential for analyzing and designing energy-efficient systems. 6. Conservation Laws : Various conservation laws, such as the conservation of mass, momentum, and energy, are fundamental principles that govern the
Prepared by: MYRINE YSOBELLE S. SIOCO, REE, RME, LPT ENMECH 1 – ENGINEERING MECHANICS
CAMARINES NORTE STATE COLLEGE
F. Pimentel Avenue, Brgy. 2, Daet, Camarines Norte
COLLEGE OF ENGINEERING
Absolute Metric (CGS) centimeter (cm) sec dynea (gm-cm/sec^2 ) gram (gm) Absolute Metric (MKS) meter (m) sec newtona (kg-m/sec^2 ) kilogram (kg) *Derived Units Table 1.3-2. Conversion of Equivalents Length Power 1 in = 2.450 cm 1 hp = 550 ft-lb/sec = 76.04 kg-m/sec^2 1ft = 12 in = 30.48 cm 1 hp = 0.7457 kW = 1.014 metric hp 1 mile = 5280 ft = 1.609 km = 1,760 yards Velocity Force 88 fps = 60 mph = 96.54 km/hr 1 lb = 0.4536 kg = 4.448 N Acceleration Pressure g = 32.2 fps^2 = 9.81 m/s^2 1 atm = 14.7 psi = 760 mmHg = 1.013 x 10^5 nt/m^2 Volume 1 cu. ft = 7.481 gallons = 28.32 liters LEARNING ACTIVITY NO. 1 : UNIT CONVERSION: Tell My Partners Convert the following units of measurements from one unit to another and round-off to two decimal places.
- 1000 gallons to _______ cu.ft
- 5088 miles to _______ km
- 1000 cu. ft to _______ cu. m
- 120 km/hr to _______ fps
- 500 N to _______ lbs.
- 32.2 psi to _______ mmHg
- 760 ft-lb/sec to _______ metric hp
- 1000 m to _______ ft.
- 100 mph to _______ fps
- 760 kW to _______ ft-lb/sec 1.4 SCALAR AND VECTOR QUANTITIES In physics and engineering, quantities can be classified into two main categories: scalar and vector quantities. Understanding the difference between these two types of quantities is essential for performing accurate calculations, analyzing problems, and interpreting results in various fields.
- Scalar Quantities : Scalars are quantities that have only magnitude (size) and no direction. They can be described by a single numerical value, and their units are typically the same as the corresponding base or derived units. Examples : mass, speed, temperature, and energy. Scalars can be added, subtracted, multiplied, and divided using standard arithmetic operations.
- Vector Quantities : Vectors are quantities that have both magnitude and direction. They are represented by arrows, where the length of the arrow represents the magnitude, and the direction of the arrow represents the direction of the quantity. Vectors are typically represented by bold letters or letters with an arrow above them, such as 𝐅 for force. Examples : displacement, velocity, acceleration, and force.
Prepared by: MYRINE YSOBELLE S. SIOCO, REE, RME, LPT ENMECH 1 – ENGINEERING MECHANICS
CAMARINES NORTE STATE COLLEGE
F. Pimentel Avenue, Brgy. 2, Daet, Camarines Norte
COLLEGE OF ENGINEERING
Scalar and vector quantities are essential in various fields including physics and engineering. They are used to describe and analyze motion, forces, and other physical phenomena. LEARNING ACTIVITY NO. 2 : SCALAR AND VECTOR QUANTITIES Identify the following statement if it is s a scalar or vector quantities.
- If a time is multiplied by a velocity, is the resultant quantity a vector quantity or a scalar quantity? Ans. _________________________________________________________
- If an acceleration is multiplied by a time, is the resultant quantity a vector quantity or a scalar quantity? Ans. _________________________________________________________
- If a force is divided by a time, is the resultant quantity a vector quantity or a scalar quantity? Ans. _________________________________________________________
- If a speed is multiplied by a time, is the resultant quantity a vector quantity or a scalar quantity? Ans. _________________________________________________________
- If an area is multiplied by a length, is the resultant quantity a vector quantity or a scalar quantity? Ans. _________________________________________________________
- If a mass is multiplied by an acceleration, is the resultant a vector quantity or a scalar quantity? Ans. _________________________________________________________
- If a mass is multiplied by a velocity, is the resultant a vector quantity or a scalar quantity? Ans. _________________________________________________________
8. A weather forecast states the temperature is predicted to be − 15 °C the following
day. Is this temperature a vector or a scalar quantity? Ans. _________________________________________________________
- The car accelerated North at a rate of 6 meters per second squared. Ans. _________________________________________________________
- The player was running 5 miles an hour towards the end zone, 5. 25 km Ans. _________________________________________________________ LEARNING ACTIVITY NO. 3: SCALAR AND VECTOR QUANTITIES: T Charts DIRECTIONS : Create a T Chart that identifies and illustrates examples of scalar and vector quantities. Think of three examples of each and write them in the boxes underneath each cell. Use a combination of scenes, characters, and props to create a visualization to represent each example. Example of Scalar and Vectors Vector Scalar Displacement Lift Length Area Weight Movement Temperature Energy Acceleration Velocity Voltage Pressure Momentum Thrust Time Speed Drag Power
Prepared by: MYRINE YSOBELLE S. SIOCO, REE, RME, LPT ENMECH 1 – ENGINEERING MECHANICS
CAMARINES NORTE STATE COLLEGE
F. Pimentel Avenue, Brgy. 2, Daet, Camarines Norte
COLLEGE OF ENGINEERING
1.5 INTRODUCTION TO FREE-BODY DIAGRAMS
Free-body diagrams are a powerful tool used in physics and engineering to analyze and visualize the forces acting on a body or system. They are essential for understanding the relationships between forces and the resulting motion, as well as for solving problems involving statics and dynamics. Purpose : Free-body diagrams are used to represent the forces acting on an object or system without including any other objects or surroundings. They help simplify complex situations by isolating the object of interest and displaying only the relevant forces. Components : A free-body diagram consists of a simple representation of the object or system being analyzed, usually drawn as a dot, a shape, or an outline. The forces acting on the object are represented by arrows, pointing in the direction of the force and originating at the point where the force is applied. The length of the arrows is proportional to the magnitude of the force. Steps to Draw a Free-Body Diagram: a. Identify the object or system of interest and isolate it from its surroundings. b. Determine all the forces acting on the object, including their directions and points of application. c. Draw a simple representation of the object and add arrows for each force, with the tail of the arrow at the point of application and the direction of the arrow indicating the direction of the force. d. Label each force with its type or symbol, and include any known magnitudes. References: Singer, F. (1975). Engineering Mechanics Statics and Dynamics. Third Edition. Beer, F.P., Johnston, E.R., DeWolf, J.T., & Mazurek, D.F. (2017). Mechanics of Materials. New York, NY: McGraw-Hill Education. Gere, J.M., & Goodno, B.J. (2017). Mechanics of Materials. Boston, MA: Cengage Learning. Hibbeler, R.C. (2012). Engineering Mechanics: Statics & Dynamics. Upper Saddle River, NJ: Pearson Prentice Hall. Tongue, B.H., & Sheppard, S.D. (2017). Dynamics: Analysis and Design of Systems in Motion. Hoboken, NJ: John Wiley & Sons. White, F.M. (2016). Fluid Mechanics. New York, NY: McGraw-Hill Education. https://byjus.com/jee/free-body-diagram/ https://en.wikipedia.org/wiki/Free_body_diagram https://whatispiping.com/free-body-diagram-definition-examples/ http://hyperphysics.phy-astr.gsu.edu/hbase/freeb.html https://byjusexamprep.com/free-body-diagram-i https://www.storyboardthat.com/lesson-plans/motion/vector-or-scalar-quantities
