Simple Machines
Simple Machine Selfie
Try to be original when finding simple machines around your house or neighborhood. You can find them in unique places! Link to the activity is to the right. Simple Machine Practice Problems Use the presentations above to help you answer these questions. |
Lever
There are three different types of levers: A way to remember where the fulcrum, resistance and effort are use the mnemonic device: FRE 123 1st class: Fulcrum is in the middle, MA can be greater or less than 1. 2nd class: Resistance is in the middle, MA is always greater than 1. 3rd class: Effort is in the middle, MA is always less than 1. |
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Wheel and Axle The axle is the smaller circumference and the wheel is the larger circumference. The larger the wheel and the smaller the axle the easier it is to turn, which means the greater the MA. These are found in more places than you would think. In a car the steering wheel is a great example. The part you turn is the wheel and the steering column (that's the small shaft that goes to your power steering pump) spins as a result. Also, think about a door knob. |
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Pulley
Fixed: like a first class lever, IMA is always 1 Movable: like a second class lever, IMA of 2 Block and Tackle (1 rope): fixed and movable pulleys in combination, IMA is equal to the number of strands opposing the force of the load Pulleys in Combination (multiple ropes): the output of one pulley system becomes the input of another system, IMA(total)=IMA(1)*IMA(2)*IMA(3)*... |
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Inclined Plane A flat surface set at an angle or incline with no moving parts. They are all over the place and often used as ramps for houses and trucks. |
Wedge It functions as a moving inclined plane. Think of things like axes, chisels, and door stoppers. |
Screw Two components: an inclined plane wrapped around a cylinder and a wheel and axle use to create rotary motion. These are used in places where you want an extremely high mechanical advantage such as cheap car jacks. They change rotary motion into linear motion resulting in an incredibly large MA. One of the downsides is a large amount of friction. |
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Gears, Pulley Drives and Sprockets
These three power train elements transfer energy through rotary motion.
They change: speed of rotation, direction of rotation, and amount of torque available to do work. Idler Gears: allow the driver and driven gears to rotate in the same direction. |
Gears, Pulleys, and Sprockets Practice Problems
Use the presentation above to help you answer these questions. |
Design Challenge |
Review |