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Simple Machines. What is a Machine?. A machine is a device that helps us perform tasks. How are machines used?. change energy from one form into another transfer forces change the direction of a force change the magnitude of a force change distance or speed. Real simple machines.
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What is a Machine? • A machine is a device that helps us perform tasks.
How are machines used? • change energy from one form into another • transfer forces • change the direction of a force • change the magnitude of a force • change distance or speed
Real simple machines • 1. State the main function or functions of each of the following machines: • (a) an axe • (b) a tennis racket • (c) a round doorknob • (d) a screwdriver • 2. Give two or three examples, of simple machines in the kitchen that increase the force you apply.
Two Families All machines can be grouped into two categories: • The Lever Family • The Inclined Plane Family
Complex machines • A machine that is composed of two or more simple machines
A lever is a rigid bar that can rotate freely around a support called a fulcrum. Load Fulcrum The Lever Family
dL dE FL FE Load Fulcrum Distance to the Effort Distance to the Load Force of the Load (mass) x 9.8 Force of the Effort
First Class Lever FL FE • In a first-class lever, the fulcrum is between the load and the effort force. Examples include a shovel or pry bar
Second Class Lever FL FE • In a second-class lever, the load is between the fulcrum and the effort force. Examples include a wheel barrow
Third Class Lever FL FE • In a third-class lever, the effort force is exerted between the fulcrum and the load. Examples include a fishing rod