1. Basic Theories and Math
Chapter 8
Basic Theories and Math

2. Matter All matter consists of atoms. Atomic structure Protons
Are positively charged particles.
Electrons
Are negatively charged particles.
Neutrons
Have no electrical charge.

3. States of Matter (cont’d)
By adding or removing heat, matter can change states.

4. Mass and Weight Mass Weight 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.

5. Size An object’s size is related to its mass.
Size dimensions are typically stated by length, width, and height.
Volume is the product of all three.

6. Formulas Circumference Volume Area of a Circle
Diameter times Pi (3.14)
Volume
Length times width times height
Area of a Circle
Pi (3.14) times the radius squared

7. Proportions Ratios can also be expressed as proportions.
Coolant is often mixed 50% water and 50% coolant. This is a 1:1 ratio.
The air/fuel mixture is typically 14.7:1. This means 14.7 parts of air are mixed with 1 part of fuel.

8. 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.

9. Automotive Forces Balanced forces are in equilibrium.
Turning forces can cause an object to rotate.
Centrifugal and centripetal forces are either away from or towards the center of a circle.
Pressure is a force applied against an object and measured in unit of force per unit of surface area.

10. Motion
When forces on an object do not cancel out, they will change the object’s speed, direction or motion, or both.
The resistance to change is called inertia.
When a forces overcomes inertia, the object gains momentum.

11. Rates Speed is the distance an object travels in a set amount of time.
Calculated by dividing the distance traveled by the time to travel the distance.
Velocity is speed in a particular direction.
Acceleration is an increase in speed.
Deceleration is a decrease in speed.

12. 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.

13. Friction
Slows or prevents motion of two objects or surfaces that touch.
Friction occurs in solids, liquids, and gases.
Good friction – brake system
Bad friction – metal-on-metal contact in an engine

14. Changing Friction
Mechanical friction can be reduced by using bearings and lubricants.
Air resistance is reduced by improving vehicle body design to reduce drag.
Brake system effectiveness can be either increased or decreased by the quality of friction components.

15. 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.

16. Work Being Performed

17. 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.

18. Torque Multiplication

19. Liquids Fluids conform to the shape of their container.
Basically incompressible.
Can transmit force and motion.
Liquids exert pressure on immersed objects.
If pressure is enough the object will float.

20. 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.

21. Sample Hydraulic System

22. Gases
A gas is a fluid made up of particles that are in constant, random motion.
Gases fill their container.
Two gases sharing a container will mix – this is called diffusion.
The kinetic energy of a gas increases as the temperature increases.

23. 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.

24. Vacuum Scientifically is the absence of atmospheric pressure.
Generally used as any pressure less than atmospheric.
Also called low or negative pressure.
Perfect vacuum is 29.9 inches of mercury.

25. 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.

26. 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

27. The pH Scale Used to measure how acidic or basic a solution is
Scale is from 0 to 14
Distilled (pure) water is 7
Acids are between 0 and 7
Bases are between 7 and 14

28. Reduction and Oxidation (Redox)
Oxidation is when a substance combines with oxygen.
Rapid oxidation produces heat.
The addition of hydrogen atoms or electrons is reduction.
Both occur simultaneously.
Redox is any reaction in which electrons are transferred.

29. Electrochemistry
The relationship between electricity and chemical change.
Electrolysis uses current flow through a substance to cause a chemical change.
Electrolyte is a substance that conducts current as a result of breaking down its molecules into positive and negative ions.

30. Electricity and Electromagnetism
All electrical effects are caused by electrical charges – positive and negative.
Protons carry a positive charge.
Electrons carry a negative charge.
Electricity and magnetism are intertwined and inseperable.

31. Electricity
An electrical circuit is a path in which electrical current flows.
A circuit is complete when electron movement (current flow) is possible.

32. Electrical Terms Voltage Amperes Resistance
The strength of an electrical force
Amperes
The flow of electrons
Resistance
The opposition to electron flow

33. Magnets
Some materials are natural magnets – most magnets are produced.
A magnet has its atoms oriented along magnetic lines.
All magnets have a North and South pole.
A magnetic field exists between the poles.

34. Electromagnetism
A magnetic field is generated around a current carrying conductor.
Increasing the current increases the strength of the magnetic field.

35. Producing Electrical Energy
Moving a conductor through a magnetic field produces electricity.
This is how the vehicle’s generator and power generation plants produce electricity

38. Pounds per square inch gauge
15 psi
29.7 psia
10 psi
24.7 psia
19.7 psia
5 psi
14.7 psia
0 psig 0”
10 psia
10”
20”
5 psia
Vacuum
Pounds per square inch absolute