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Using Machines. Section 2. What is a Simple Machine?. A device that makes doing work easier Why???? It allows less force to be used over a longer distance. The amount of work cannot be less, only the amount of force
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Using Machines Section 2
What is a Simple Machine? • A device that makes doing work easier • Why???? • It allows less force to be used over a longer distance
The amount of work cannot be less, only the amount of force • Because W=Fd, if force becomes less, then distance has to increase to keep work the same
Why Use a Machine • Lower the amount of force • Change direction of force • Change the speed
Advantages of Simple Machines • Input force (Fin)-the force applied to the machine • Output force (Fout) the force applied by the machine to overcome resistance
Work • Work input (Win) is the work put in by the user • Work output (Wout) is the work done on the object
Conserving Energy • You do work on the machine, you transfer energy to the machine • Machine does work on the object, energy transferred to object • Energy can’t be created or destroyed • Energy transfer can’t be greater • Machine can’t create energy • So Win= or > Wout
There can never be more output than input • Only an ideal machine will the works be equal • Work input is usually larger because of friction
Mechanical AdvantageMA • The number of times a machine multiplies the effort force
Ideal Mechanical AdvantageIMA • The mechanical advantage of a perfect machine that wouldn’t include friction
Efficiency • A measure of how much work input to converted to work output • High efficiency means little friction • How could the efficiency be increased?
Actual Mechanical AdvantageAMA • The mechanical advantage including friction • Is AMA > IMA or AMA<IMA? • Why?