An introduction to simple machines.
A simple machine reduces the amount of force needed to complete a task. Simple machines make lifting, pulling and pushing things easier. They can also reduce the distance you'd normally use to move an object. Some simple machines reduce the force needed by a large amount, but one has to cover more distance than usual to lift it.
Mechanical advantage is calculable for some simple machines. Mechanical advantage shows the benefit to using simple machines. There are different formulas for each one, but they all show how the machine expands the amount of force applied to it. Simple machines have been used for many years. The wheel and axle dates back many centuries ago, and it has made a huge impact on countless civilizations. For example, the wheel and axle made transportation much easier. Carts and other wheeled vehicles provided convenience, and production has not ceased to continue. The wheel and axle mentioned in this website is a bit different, however. It is common that the axle spins as well, like a door handle or a water wheel does. The formula for mechanical advantage for this machine is the radius of the wheel divided by the radius of the axle. The other 4 simple machines include inclined planes, gears, pulleys and levers. An inclined plane decreases the amount of distance needed to move an object. Because of the incline, more force is required to push or pull the object. One can calculate the amount of work done to move the object by multiplying the force applied to the object and the distance traveled. Gears are ubiquitous among bikes, and are the working insides of clocks. If two gears are connected, and one is rotating, it will turn the other. Every time two gears are connected and spinning, they are rotating in opposite directions. Gear ratio is the ratio between the first and last gear's rate of rotation. Pulleys are capable of making things much easier to lift. One's mechanical advantage is equal to the amount of times the string is looped around two pulleys, as exemplified to the left. There are three classes of levers. Levers are very common, and are used almost every day. First class, second class and third class levers all modify the amount of work you need to lift something. Depending on the class, input force is put in at a certain spot, and output force is multiplied. A first class lever may be a teeter totter or scissors. An example of a second class lever is a wheelbarrow. An example if a third class lever is a fishing rod or a hockey stick. |
WHEEL AND AXLE DIAGRAM
INCLINED PLANE DIAGRAM
GEAR DIAGRAM. RATIO = 2 : 1
PULLEY DIAGRAM
LEVER DIAGRAM
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