Energy (The ability to do work) Potential energy: due to position ex. bungee jumper Kinetic energy: due to motion ex. baseball Thermal energy: heat ex. stove element Electrical energy: ex. power outlet Light energy: ex. light bulb Sound energy: ex. speaker Chemical energy: found in chemicals Nuclear energy: found in uranium

Work Force: push or pull, measured in Newtons (N) Distance is measured in meters (m) Work = force x distance Work is done when a force is applied to an object and it moves If you are pushing on a wall is this work? If you lift a box and walk across a room, is this work?

Incline Plane A simple machine Allows 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 hill You can push an object up or down instead of lifting it

Levers They are bars that pivot on a fulcrum An effort force is required to move a load The distance from the load to the fulcrum is the load distance The distance from the fulcrum to the effort is the effort distance

First Class Lever The fulcrum is between the load and the effort Used for lifting, prying, cutting Ex. teeter totter, scissors, pliers, claw hammer when pulling nails, crowbar, oar on a rowboat or raft Draw the picture on page 134

Second Class Levers The fulcrum is at one end, the effort at the other end and the load in between them Ex. wheelbarrow, bottle opener, nut cracker, Achilles tendon Draw the picture on page 136

Third Class Lever The fulcrum is at one end, the load at the other end and the effort in between them Used when a job requires speed Ex. 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 Body Triceps: class 1 Biceps: class 3 See page 138

Distance Multipliers Examples include fishing rods, hockey sticks, axes, mallets They move a load through a large distance with little effort distance When distance is multiplied there is a speed advantage Commonly in third class levers

Force Multiplier A simple machine which moves a large load easily A small effort on the lever, puts a large force on the load First and second class levers are force multipliers

Pulleys A grooved wheel with a rope threaded around it The load is attached at one end of the rope, effort is applied at the other end When 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 Axle Every 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 By Friction Heat Poor combustion (if fuel is used)

Efficiency A comparison to the work done with the energy used that is used to do work No machine is 100 % efficient When you cook food, some heat is lost to warm the air above the pot (convection)

In the House Being efficient is a way to conserve money as well as protect the environment Appliances around the home have energy ratings, measured in kilowatt hours A kilowatt hour is the amount of electricity used when 1000 watts is used for 1 hour

Fossil Fuels Most of the energy in Canada comes from the burning of fossil fuels (oil, gas) They pollute the environment and are non- renewable To 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 Energy Wind power Solar power Ballard fuel cell