SIMPLE MACHINES Chapter 5 Notes

Machine A device that helps make work easier Changes the size or direction of the force Simple Machine – A type of machine that uses only one kind of motion to make work easier Complex Machine – a combination of simple machines.

Six Simple Machines 1. Lever – a bar that pivots around a fixed point (fulcrum) 1st Class – the fulcrum in between the input force and output force input output fulcrum

Levers continue: 2nd Class – the output force is between the fulcrum and the input force. 3rd Class – the input force is between the fulcrum and the output force output input fulcrum fulcrum input output

Force Distance Trade Off What increases for work input must decrease for work output. As force increases, distance decreases. As force decreases, distance increases.

Mechanical Advantage How much force a machine is applying for you. MA = Output Force ÷ Input force The larger the mechanical advantage, the easier a machine makes your work.

Mechanical Efficiency Measures how much friction a machine has. More Friction equals less work output. ME = (work output ÷ work input) 100 Measured as a percentage

Simple machines 2. Inclined Plane – ramp ( forms a right angle) Applies a smaller force over a longer distance

Simple Machines 3. Wedge – A double inclined plane Ex: knife, doorstop, ax head

Simple Machines 4. Screw – an inclined plane, wrapped around a cylinder 5. Wheel and Axle – a simple machine with two circular objects of different sizes. Wheels with teeth

Simple Machine 6. Pulley – a grooved wheel that holds a cable. Fixed Pulley – the pulley is attached and changes the direction of the force only Movable – increases force without changing direction Block and Tackle – A fixed pulley and a movable pulley are used together for a greater mechanical advantage