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Using Simple Machines to do Work More Easy. Devices that allow us to perform the same amount of work more easily. Simple Machines Work in One of 3 Ways . Can take the force exerted by the individual and redirect it Can turn a small effort or force into a larger force (mechanical advantage)
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Using Simple Machines to do Work More Easy Devices that allow us to perform the same amount of work more easily.
Simple Machines Work in One of 3 Ways • Can take the force exerted by the individual and redirect it • Can turn a small effort or force into a larger force (mechanical advantage) • Can magnify the distance that a force acts on
Review Work = (force) (distance) or W = Fd Force = (mass)(acceleration) or F = ma
Machines do not reduce the amount of work needed to perform a task, they reduce the effort needed from the user.
3 Kinds We Will Consider • Lever • Inclined Plane • Pulley
The Lever • Is a narrow beam that rotates around a single point called the fulcrum • By placing an object to be moved, called the load, at one point on the beam and by applying an effort at another point the object can be moved more easily
1st Class Lever • 1st class – where the fulcrum lies between the load and the effort Fulcrum Load Effort
1st Class Lever Effort Load Fulcrum
2nd class lever • 2nd class levers where the fulcrum lies at one end and an effort is placed at the other end. • The load lies in between Effort Fulcrum Load
3rd Class Lever • 3rd class lever – where the effort is applied between the load (W) and the fulcrum Fulcrum Effort Load
Review of Levers 1st Class Lever Load – Fulcrum – Effort 2nd Class Lever Fulcrum – Load – Effort 3rd Class Lever Fulcrum – Effort - Load
Formula for Levers Effort X distance from the fulcrum = weight X distance from the fulcrum The longer the lever, the greater the force amplification and the easier it is to move the load. However, the longer the lever arm, the shorter the distance will move But - Too heavy of a mass or too long of lever the lever will break.
Inclined Plane • Device designed to reduce the force needed to raise an object. • For example, pushing a load up a ramp onto a platform requires less force than lifting the load onto the platform. • Ramps and steps are forms of inclined planes.
Screw • Screw is an inclined plane wrapped in a spiral around a shaft.
Remember! An inclined plane does not reduce the amount of work being done – It simple reduces the force necessary to complete that work by creating a mechanical advantage.
Pulleys • is a wheel over which a rope or belt is passed for the purpose of transmitting energy and doing work.
Pulleys Reduce the effort to raise an object or it redirects the applied force, depending on the type of pulley.
Flagpole • Raising a flag by pulling down on the line to which the flag is attached. • It does not reduce the effort needed to raise the object, it redirects the applied force.
How much mass can a lever handle? Apparatus for lab looks like this: