Ch07 Basic Theoriesand Math Rev
- 1. Chapter Seven Basic Theories and Math
- 2. Objectives Describe how all matter exists. Explain what energy is and how energy is converted. Calculate the volume of a cylinder. Explain the forces that influence the design and operation of an automobile. Describe and apply Newton’s Laws of Motion to an automobile.
- 3. Objectives (Cont’d) Define friction and describe how it can be minimized. Describe the various types of simple machines. Explain the difference between torque and horsepower. Differentiate between a vibration and a sound. Explain Pascal’s Law and give examples of where it is applied to an automobile.
- 4. Objectives (Cont’d) Explain the behavior of gases. Explain how heat affects matter. Describe what is meant by the chemical properties of a substance. Explain the difference between oxidation and reduction. Describe the origin and practical applications of electromagnetism.
- 5. Matter All matter consists of atoms. Atomic structure: Protons Are positively charged particles. Electrons Are negatively charged particles. Neutrons Have no electrical charge.
- 6. States of Matter Solid Particles are held together in a rigid structure. Liquid Particles break away from structure and form a solution. Gas Atoms or molecules break free from the body of the liquid.
- 7. Forms of Energy Chemical Electrical Mechanical Thermal Radiant Nuclear
- 8. Common Automotive Energy Conversions Chemical to thermal Fuel burning in the cylinder Chemical to electrical Battery Electrical to mechanical Starter motor Thermal to mechanical Engine Mechanical to electrical Generator Electrical to radiant Light bulbs
- 9. Mass and Weight Mass Is the amount of matter in an object. Size is related to mass. Weight Is a force measured in pounds or grams. Is caused by gravitational pull.
- 10. Formulas Circumference Diameter times Pi (3.14) Volume Length times width times height Area of a circle Pi (3.14) times the radius squared
- 11. Calculating Engine Displacement CID = Pi x R (squared) x L x N Pi = 3.14 R = the radius of the cylinder opening (or the bore divided by 2) L = the length of the stroke N = the number of cylinders
- 12. Bore and Stroke
- 13. Compression Ratio Compression ratio is the ratio of the volume in the cylinder above the piston when at BDC to the volume in the cylinder above the piston when at TDC. CR = volume of cylinder at BDC divided by the volume of cylinder at TDC.
- 15. Force Force can be applied to objects by direct contact or from a distance. Forces can be applied from any direction and with any intensity. When two or more forces are applied to an object, the combined force is called the resultant.
- 16. Time Time is defined as a measurement of the duration of an event. Time is measured in seconds, minutes, and hours. Speed is the distance an object travels in a given amount of time.
- 17. Newton’s Laws of Motion An object at rest tends to remain at rest, and an object in motion tends to stay in motion. When a force acts upon an object, the motion of the object will change. For every action, there is an equal and opposite reaction.
- 18. Work Work is done when a force moves a certain mass a specific distance. Work is equal to the applied force multiplied by the distance the object moved: Force x Distance = Work Work is measured in foot-pounds, watts, Newton-meters, or joules.
- 20. Torque Torque is a force that does work that tends to rotate or turn things. Torque is force times leverage. To have torque, it is not necessary to have movement.
- 22. Horsepower Horsepower is the rate at which torque is produced. One horsepower is equal to 33,000 foot-pounds of work in one minute. One horsepower is equal to 746 watts, 545 Btu, 1055 joules, or 252 gram-calories.
- 24. Vibrations Frequency The number of times a vibration occurs in one second Measured in Hertz (cycles per second) Amplitude The strength or intensity of a vibration
- 25. Sound Pitch Based on frequency Decibel The relative loudness Resonance Caused by two vibrations with nearly the same frequency Overtone A higher tone heard with the waves of the original tone Harmonics Result from two or more tones at the same time Intensity Amount of energy
- 26. Laws of Hydraulics Hydraulics is the study of liquids in motion. Liquids are non-compressible. Pressure is transmitted equally in all directions. Hydraulics can provide a mechanical advantage. Pressures and mechanical advantage are mathematically computed.
- 27. A Sample Hydraulic System
- 28. Behavior of Gasses Volume and pressure of a gas are inversely proportional. The pressure of a gas at constant volume will increase as its temperature increases. The higher the temperature of a gas, the higher the volume.
- 29. Heat Temperature is an indication of an object’s kinetic energy. Heat is measured in Btu, calories, or joules. Anything that gives off heat is a source of heat.
- 30. Methods of Heat Transfer Convection Transfer of heat by movement of a heated substance Conduction The movement of heat through a material Radiation The transfer of heat by infrared waves
- 31. Electrical Terms Voltage The strength of an electrical force Amperes The flow of electrons Resistance The opposition to electron flow
- 32. Summary Matter is anything that occupies space, and it exists as a gas, liquid, or solid. Energy is the ability to do work. Mass is the amount of matter in an object. Volume is the amount of space occupied by an object in length, width, and height.
- 33. Summary (Cont’d) The forces required to maintain circular motion are called centripetal and centrifugal force. Pressure is a force applied against an opposing object. Momentum is when a force overcomes static inertia.
- 34. Summary (Cont’d) Speed is the distance an object travels in a set amount of time. Friction is a force that slows or prevents motion of two objects that touch. Torque is a force that tends to rotate things. Power is a measurement for the rate at which work is done.
- 35. Summary (Cont’d) Hydraulics is the study of liquids in motion. The pressure law states that the pressure exerted by a gas at constant volume increases as the temperature is increased. Heat is a form of energy caused by the movement of atoms. The most common way to produce electricity is to use a coil of wire and magnet.