Welcome David Ruiz I will be using your LBCC email to communicate with you about the class. I will NEVER send scores/grades to your email address unless you ask me to do so. Syllabus Read over carefully
Welcome Being successful. Your success matters to me. I can only help so much. Ultimately your success is your responsibility! Make a schedule. Set aside time for: Studying Work Household chores Family Fun When it s time to relax, relax! Completely separate your fun time from your study time. If you try to mix them you won t do either one well. Stick to your schedule. When it s time to study, block out distractions and use the time efficiently. Study in small blocks of time ~ 1 hour. Review old material.
Preliminaries Creating a comfortable learning environment Ask questions / participate Civility Respect for others Interruptions / Distractions Cell phones No coarse language / profanity / humor of sexual nature Food & Drink only in classroom (not lab area)
Supplies / Resources Supplies: Textbook & workbook Lab / log book Flash Drive Pens / pencils / paper Safety glasses / gloves Long pants (jeans), closed toed sturdy shoes, cotton (long sleeved shirt) Computer with word processing / spreadsheet software Open Office or other word processing software
Syllabus Contact me by phone or email Lecture: 1700-1950 Lab times Office hours
Energy Systems An energy system is a method by which energy is transferred and work is done. There are four basic types of energy systems: Mechanical Fluid Electrical Thermal Translational Rotational Pneumatic Hydraulic
Energy Systems In every energy system there is: something pushing (or pulling) something moving (or distorting) something opposing the motion Mechanical Prime Mover What s moving What s opposing Fluid Electrical Thermal
Mechanical Systems Simple mechanical systems or devices. Definitions Machine Mechanical system Simple machine Mechanical Advantage Rigging Lifting
Math Skills A portion of this course involves developing math skills that you will need in future coursework. Today s topics include: Exponents Powers of Ten Scientific Notation Metric Prefixes Rounding And the beloved equation
MACHINES What is the function of a machine? A machine transforms energy into motion to perform useful work.
FRICTION And now a word (or two) about friction. Friction is a force acting between objects which are in contact with one another. Smooth surfaces generally exhibit less friction than do rough surfaces. Disadvantages: More friction requires more force by machine. Increase in heat. Advantages: Keeping parts in contact allows machines to work How do you decrease friction between parts of a machine?
MECHANICAL SYSTEM What is a Mechanical System? A mechanical system is a collection of machines operating together to transform energy into useful work.
SIMPLE MACHINES What is a simple machine? A device that makes work easier by changing the amount and/or the direction of force acting on a object A simple machine has only one motion
SIMPLE MACHINES What are some simple machines? Lever Inclined plane Wheel and Axle Simple machines are the building blocks of all modern machines
SIMPLE MACHINES Why use a simple machine? Simple machines can magnify forces. A small force in can produce a large force out. Simple machines provide a MECHANICAL ADVANTAGE
MECHANICAL ADVANTAGE Ratio of the output force of a device to the input force of a device Four factors must interact to gain a mechanical advantage 1. Input force 2. Output force 3. Distance 4. Speed
MECHANICAL ADVANTAGE The amount of work done by a hand on the hammer equals the amount of work done by the hammer in pulling out the nail
INCLINED PLANE What is the advantage? Sloped surface makes lifting easier
THE SCREW Is the screw a simple machine? Yes! The screw is an just an inclined plane wrapped around a rod used to hold objects together.
THE WEDGE Is the wedge a simple machine? Yes! The wedge is two inclined planes placed back-to back.
THE LEVER What are the parts of a lever? Three parts of a lever: 1. Effort arm 2. Fulcrum 3. Resistance arm
THE LEVER What are the different classes of levers? Class 1 or Class A Class 2 or Class B Class 3 or Class C
LEVER MECHANICAL ADVANTAGE How is the mechanical advantage of a lever determined? Take the ratio of the length of the effort arm to the length of the resistance arm Is this true for all levers?
THE WHEEL and Axle One common use of the wheel is the pulley A pulley is a wheel with a chain or rope going around it There are two types: 1. Fixed 2. Movable
THE FIXED PULLEY What is the purpose of the fixed pulley? The fixed pulley changes the direction of the force The fixed pulley does not magnify the force
THE MOVEABLE PULLEY What is the purpose of the moveable pulley? Attached to the load Carries the weight of part of the load RUNNER
PULLEY MECHANICAL ADVANTAGE How is the mechanical advantage of the pulley determined? By the number of ropes supporting the load. What is the mechanical advantage of this pulley system? 4 How much force would have to be applied to lift the 200kg block? 50 kg