PLTW POE

Which lever has an IMA <1

3rd class

Which lever has an IMA >1

2nd class

Which lever has an IMA that can be less than or greater than 1

1st class

What are the 6 simple machines?

Levers, screws, wedges, pulleys, inclined planes, and a wheel and axle

How do you find the IMA of a lever?

They’re all on the formula sheet :)

Which circuit flows in only one direction?

series

Where do you measure current?

Ammeter, put it into the circuit (hope R=0 here to not disturb current)

Where do you measure voltage?

Voltmeter, observer, (R=infinity), should be placed parallel to circuit, outside of it.

Where do you measure resistance?

Ohmmeter, on either side of a resistor or on the device to see how much it is resisting.

How do you find current and voltage in a series circuit?

Current stays the same, add up the voltages.

How do you find current and voltage in a parallel circuit?

Add up the currents, voltage stays the same.

Equation for power into a system?

IV(current*voltage)

Equation for power out of a system?

Work/time - J/s

Moment of inertia formula

bh³/12

Moment of inertia units

in^4

What letter symbolizes max deformation?

M

Moment =

force/distance from pinned connection

Moment vs moment of inertia

Moment of inertia is based on the cross sectional area of a beam (bh³/12) moment is based on force and distance from one fixed point (fD)

Moment

Basically torque, f*d, in Nm

Unit for beam deflection

in

failure point, yield point, tensile strength, proportional limit

Blue, green, orange, red

Average kinetic energy of particles in an object

temperature

How to find heat

Q=mc(T1-T0) (q= heat energy, m=mass, c=specific heat)

The transfer of thermal energy by movement of fluid (liquid or gas) is called

convection

Which law of thermodynamics says "If two systems are separately found to be in thermal equilibrium with a third system, the first two systems are in thermal equilibrium with each other"

the zeroth law

Which direction is positive in RPM?

counter-clockwise

Alternative Energy

Any source of energy other than fossil fuels that is used for constructive purposes.

Ampere

The unit of electric current in the meter-kilogram-second system of units. Referred to as amp and symbolized as A.

Conduction

The transfer of heat within an object or between objects by molecular activity, without any net external motion.

Convection

Process by which, in a fluid being heated, the warmer part of the mass will rise and the cooler portions will sink.

Current

The net transfer of electric charge (electron movement along a path) per unit of time.

Electrical Energy

Energy caused by the movement of electrons.

Electricity

The flow of electrical power or charge.

Electromagnetic Energy

Energy caused by the movement of light waves.

Electrolysis

The process separating the hydrogen-oxygen bond in water using an electrical current.

Energy

The ability to do work.

Entropy

The function of the state of a thermodynamic system whose change in any differential reversible process is equal to the heat absorbed by the system from its surroundings divided by the absolute temperature of the system.

First Law of Thermodynamics

The law that heat is a form of energy, and the total amount of energy of all kinds in an isolated system is constant; it is an application of the principle of conservation of energy. Also known as conservation of energy.

Fuel Cell Stack

Individual fuel cells that are combined in series

Heat

Energy in transit due to a temperature difference between the source from which the energy is coming and where it is going

Kelvin

The scientific unit in which absolute temperature is measured. Symbolized by K.

Line of best fit

A straight line that best represents all data points of a scatter plot. Regression line/trend line.

Ohm

The unit of resistance. Ω.

Ohm’s Law

States that the direct current flowing in an electrical circuit is directly proportional to the circuit’s voltage and inversely proportional to the resistance.

Radiation

The process by which energy is transmitted through a medium, including empty space, as electromagnetic waves

Renewable energy

A resource that can be replaced when needed

Resistance

The opposition a device offers to the flow of direct current

R-value

The measure of resistance to heat flow

Second Law of Thermodynamics

Energy flows from hot to cold unless something is done to stop it.

Temperature

A property of an object which determines the direction of heat flow when the object is placed in thermal contact with another object. Average kinetic energy of particles in an object.

Thermal equilibrium

Refers to the property of a thermodynamic system in which all parts of the system have attained a uniform temperature which is the same as that of the system’s surroundings.

Thermodynamic system

A part of the physical world as described by its thermodynamic properties such as temperature, volume, pressure, concentration, surface tension, and viscosity.

Thermodynamics

The study of the effects of work, heat, and energy on a system.

U-value

A measure of thermal transmittance through a material.

Volt

The unit of potential difference symbolized as V.

Voltage

The potential difference measured in volts. The amount of work to be done to move a charge from one point to another along an electric circuit.

Absolute Pressure

The total pressure exerted on a system, including atmospheric pressure.

Atmospheric Pressure

The pressure exerted by the weight of the atmosphere.

Check Valve

A valve that allows flow in one direction but prevents flow in the opposite direction.

Compressor

An air pump that compresses air into a receiver tank.

Crank

A part of an axle or shaft bent out at right angles, for converting reciprocal to circular motion and vice versa.

Cylinder

A device used to convert fluid power into mechanical power in the form of linear motion.

Directional-Control Valve

Used to control which path fluid takes in a circuit.

Double-Acting Cylinder

A cylinder that can act under pressure in both directions (extend and retract) to move a load.

Flow Velocity

The distance the fluid travels through a system in a given period of time.

Fluid Power

The use of a fluid (liquid or gas) to transmit power from one location to another.

Lubricator

A device used to spray an oil mist into the stream of a pneumatic system.

Piston

A sliding piece moved by or moving against fluid pressure which usually consists of a short cylindrical body fitting within a cylindrical chamber or vessel along which it moves back and forth.

Pressure Regulator

A type of pneumatic pressure control valve that controls the maximum pressure in a branch of a circuit.

Pressure Relief Valve

A type of pressure control valve that limits the maximum pressure in a hydraulic or pneumatic circuit.

Pump

A device used to create flow in a hydraulic system.

Receiver Tank

A device that holds the compressed air in a pneumatic system.

Reservoir

The tank that holds the fluid in a hydraulic system.

Single-Acting Cylinder

A cylinder that acts under pressure in one direction only and returns automatically when the pressure is released.

Solenoid

A switching device that uses the magnetic field generated by an electrical current for actuation.

Transmission Lines

Used to transport fluid in a circuit.

Valve

Any device that controls, either automatically or manually, the flow of a fluid.

Viscosity

A measure of a fluid’s thickness or resistance to flow.

Volume

The amount or quantity of something.

Moment of inertia

The mathematical property of a cross-section that gives important information about how that cross-sectional area is distributed about a centroidal axis. Changes based on plank vs joist. bh³/12

Modulus of Elasticity

Ratio of increment of stress to increment of strain, based on chemical makeup.

Centroid?

Add all areas, find all y-values, multiply, then do Ay/A. Same for x to find x-value for it

Trusses?

EFx=AB+ACx, EFy=Ay+ACsin(theta), EFy=By+BCsin(theta). If angles are the same and Ay and By are, AC and BC are too

Smallest thing a material can be broken down into while retaining its properties

Atom

Metals

Good conductors, 1-3 valence electrons

Nonmetals

Most are gases at room temp, solids brittle, dry, poor heat and electricity conductor

Metallic

• pure metal

• metal alloys

• good conductors

• strength and plasticity

Ceramic

• Compound of metal+nonmetal

• Good insulators

• Strength at high temps and brittleness

Organic

• are or were living at one point

• carbon and hydrogen

• genetically alterable

• renewable, sustainable

Polymeric

• mostly organic

• low density

• flexibility and elasticity

• plastics/elastomers

Composite

• made of more than one

• layer- alternate layers binded together

• particulate- discrete particles of one material surrounded by a matrix of others

• Fiber-reinforced- Composed of contiunous or discontinuous fibers in a matrix of another

Thermoelectric

Electrical stimuli provoke thermo responses; thermo stimuli provoke electrical responses

Flow Shop

Larger quantities of products

Production line

Special purpose machines

Job Shop

Small quantities of products 

Large variety of products

Products move through the shop to various machines

General-purpose machines

Linked-Cell Shop

Manufacturing and subassembly cells connected to final assembly

Lean production system

One piece flow system

Project Shop

Product being manufactured cannot be easily moved during production.

Production processes are brought to the product.

Examples:Bridges, ships, large airplanes, locomotives, large machinery

Continuous Process

Large plants

Utilized in the manufacture of liquids, oils, gases, and powders

Lean Manufacturing

100% “good” units flow from process to process 

Integrated quality control (IQC)

All employees are inspectors

Rolling

Material passes through a series of rollers, reducing its thickness with each pass

Forging

Material is shaped by the controlled application of force (blacksmith)