Machines Machines Work When a force moves an

Machines, Machines

Work When a force moves an object in the direction you are pushing or pulling that object

Joule Since work involves transferring energy this is the unit for work

power Work divided by time

watt The unit describing power

machine Something that changes the direction the force goes or overcomes force

Work input The work you do on a machine – like pushing a lawnmower

Work output The work the machine does – like cutting the grass

Mechanical advantage How many times the machine multiplies force Output force/Input force

Mechanical Efficiency How much work you get out of a machine compared to what you put in it. Work output/ Work Input

Fulcrum Fixed point on a lever – can be in different positions depending on the class of lever

lever A bar rotating around a fixed point – like a teeter-totter

pulley A wheel that a rope goes over

Block and Tackle Using a fixed pulley and a moveable pulley together

Wheel and Axle Two circular objects of different sizes

Inclined Plane A straight, slanted surface like a ramp

Wedge Two inclined planes that move – like a scissors

Screw An inclined plane (flat slanted surface) wrapped around a cylinder

Compound Machine A machine made up of two or more simple machines

Simple Machine A ll machines are made from these – lever, screw, pulley, wedge, inclined plane, and wheel and axle.