energy (the ability to do work) potential energy: due to position ex. bungee jumper kinetic energy:...
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Energy (The ability to do work)
Potential energy: due to position ex. bungee jumper
Kinetic energy: due to motion ex. baseballThermal energy: heat ex. stove elementElectrical energy: ex. power outletLight energy: ex. light bulbSound energy: ex. speakerChemical energy: found in chemicalsNuclear energy: found in uranium
WorkForce: push or pull, measured in Newtons (N)Distance is measured in meters (m)Work = force x distanceWork is done when a force is applied to an
object and it movesIf you are pushing on a wall is this work?If you lift a box and walk across a room, is
this work?
Incline PlaneA simple machineAllows less effort to be expended during a
task because instead of going straight up or down a steep hill
You go back and forth across a steep hillYou can push an object up or down instead of
lifting it
LeversThey are bars that pivot on a fulcrumAn effort force is required to move a loadThe distance from the load to the fulcrum is
the load distanceThe distance from the fulcrum to the effort is
the effort distance
First Class LeverThe fulcrum is between the load and the
effortUsed for lifting, prying, cuttingEx. teeter totter, scissors, pliers, claw
hammer when pulling nails, crowbar, oar on a rowboat or raft
Draw the picture on page 134
Second Class LeversThe fulcrum is at one end, the effort at the
other end and the load in between themEx. wheelbarrow, bottle opener, nut cracker,
Achilles tendonDraw the picture on page 136
Third Class LeverThe fulcrum is at one end, the load at the
other end and the effort in between themUsed when a job requires speedEx. axes, rackets, tongs, brooms, tweezers,
shovel, ice cream scoop, hammer when hammering, hockey stick, fishing poll, bat
Draw the picture on page 137
Levers in the BodyTriceps: class 1Biceps: class 3See page 138
Distance MultipliersExamples include fishing rods, hockey sticks,
axes, malletsThey move a load through a large distance
with little effort distanceWhen distance is multiplied there is a speed
advantageCommonly in third class levers
Force MultiplierA simple machine which moves a large load
easilyA small effort on the lever, puts a large force
on the loadFirst and second class levers are force
multipliers
PulleysA grooved wheel with a rope threaded around
itThe load is attached at one end of the rope,
effort is applied at the other endWhen the effort can support the load, the
system is in equilibrium
Fixed pulley: the effort force is equal to the load force
Moveable pulley: moves with a load
Wheel and AxleEvery time you turn a doorknob you rotate a
wheel and axle, the doorknob is a wheel that turns the axle
A screwdriver is a wheel and axle, the handle acts as the wheel, the screw is the axle, as you rotate the handle the screw moves
Machines Loose Energy ByFrictionHeatPoor combustion (if fuel is used)
EfficiencyA comparison to the work done with the
energy used that is used to do workNo machine is 100 % efficientWhen you cook food, some heat is lost to
warm the air above the pot (convection)
In the HouseBeing efficient is a way to conserve money as
well as protect the environmentAppliances around the home have energy
ratings, measured in kilowatt hoursA kilowatt hour is the amount of electricity
used when 1000 watts is used for 1 hour
Fossil FuelsMost of the energy in Canada comes from
the burning of fossil fuels (oil, gas)They pollute the environment and are
non-renewableTo solve these problems we could reduce
the amount of energy we use, such as walk instead of drive
Replace inefficient appliances with more efficient ones, such as a new fridge
Use renewable energy sources
Renewable EnergyWind powerSolar powerBallard fuel cell