y10 emd

force

an action that changes the motion of an object

tension

a type of force that pulls or stretches an object

compression

a type of force that pushes or shrinks an object

torsion

when 2 forces of similar strength are applied in opposite directions on either end of an object

shear

when 2 forces of similar strength are applied in opposite directions on either face of an object

triangulation

the use of triangles to make sturdy structures

suspension

when a group of components enable a machine to move smoothly with minimal shock

arch

an opening in a structure that is curved on top

truss

a set of objects that form a sturdy structure

strut

a structural element that resists compression

tie

a structural element that resists tension

effort

the machines input force

load

the machines output force

mechanical advantage

describes how machines trade force for speed or speed for force

force advantage

easier to move a heavy object at a slower speed

speed advantage

makes the load go faster at a weaker force

pulleys

a set of wheels and ropes

levers

contain a rigid bar and a fulcrum to rotate around

1st class lever

fulcrum between effort and load

2nd class lever

load between fulcrum and effort

3rd class lever

effort between fulcrum and load

gears

a wheel with teeth interlocking to create motion

driving wheel

the wheel with the input force

driven wheel

the wheel being turned

gear ratio

#teeth on driven gear/#teeth on driving gear

idler gear

an in-between gear causing a driver and driven gear to spin in the same direction

rack and pinion

used to convert rotation and linear forces to each other

bevel gear

gears that are useful to rotate at 90 degrees

worm gear

a spiral tooth gear

compound gear

multiple gears on the same shaft

crank

an arm attached to an axel to rotate the shaft

electricity

a form of energy that causes electrons to flow

conductors

required for electricity to flow through

examples of conductors

copper, silver

insulators

stop or hinder the flow of electricity

examples of insulators

plastic, rubber

resistance

the force that opposes current in a circuit

unit for resistance

ohms

current

the flow of electrons in a circuit

unit for current

amperes (amps)

voltage

the force that pushes electrons around

unit for voltage

volts

polarity

the positive and negative terminals in a circuit

what 3 components must a circuit always have

a closed path, power supply, load

direction of current

positive to negative

series circuit

components arranged one after another

parallel circuit

both components access full power as current has two paths to travel along

series circuit vs parallel circuit

series circuit has higher total resistance, lower total current, lower total power and reduced brightness

ohms law

v = i x r

diode

limits the flow of current to one direction

capacitor

a small component that can store and release electricity

resistor

limits current in a circuit

motor

supplies motive power

lamp

uses a resistive wire that heats up so hot it emits light

led

light-emitting diode

switch

connects or disconnects a circuit

transistor

has three legs and is used as an electronic switch