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SIX SIMPLE MACHINES
Dear Diary, Today I helped Mr. Johnson lift his new piano onto his truck. He hooked me up as a movable pulley (above right) to cut the effort in half. It only took him 400 pounds of effort to lift the 800 pound piano. Later today, Mr. Johnson used me to lift a desk. He turned me into a single pulley and tied one end of my rope to the desk and pulled my other end and lifted the desk through the second floor window. Although movable pulleys can reduce the effort by half, you'd still need 100 pounds of effort to lift a 100 pound desk when I'm a single pulley. Also, when I'm a single pulley, I change the direction that an object is moving. My sister, Julie Pulley is in some blinds, helping to open and close them.
Mrs. Pulley's Diary
LEVERS
Levers can help lift heavy objects with less, the same, or more effort that it would be to just lift the object. It is less when the fulcrum (pivot point) is farther away from you. It is the same when it is in the middle. It takes more effort when the fulcrum is close to you. Levers can be used in rides like the Dumbo Ride.
A screw is an inclined plane wrapped around a pole. Screws help keep many items together by having to twist them to get them in or out, as compared to the nail which you can pull directly out. Screws can be found in items such as McDon-nalds happy meal toys.
THE SCREW
WEDGES
INCLINED PLANE
Inclined planes are basically a flat surface on a tilt. The lower that the plane is tilted then the less effort it would take to push an object. The higher it is the more effort it will take. An example of an inclined plane is a handicapped access ramp.
A wedge is two inclined planes put together that turns a downward force into an outward force. An example is an axe.
Fun Facts: ~Most complex machines in everyday life often contain many simple machines! ~ The lever is believed to have been invented in 5000 B.C.!
A wheel is a lever that can turn 360 degrees and can have an effort or resistance applied anywhere on the machine. The effort or resistance force can be applied either to the wheel or the axle. An example is a steering wheel.
WHEEL & AXLE
swimchick0511 added this comment 2010-10-10 12:00:10-05:00
good
swimchick0511 added this comment 2010-10-10 12:00:10-05:00
good