Mechanisms and Simple Machines Review
"Mechanism" comes from the Latin word for machine. A machine is a tool that is made
up of moving parts that all work together to do a certain job.
Work = Force times distance. The energy that pushes or pulls on an object is called the
force. Work only occurs if motion results from the force applied. Machines help with
work by changing the direction of motion and providing mechanical advantage.
Mechanical Advantage reduces the amount of input force and increases the distance you
Simple machines include screws, wedges, inclined planes, gears, levers, pulleys,
wheels and axles.
Gears have teeth that fit together and turn. The main type of gear used in a bicycle
is called a sprocket gear. A sprocket gear is different from other gears because its teeth
are designed to fit into the holes of a chain.
The three parts of a lever are the fulcrum, effort arm, resistance arm. Another
name for the pivot point of a lever is the fulcrum. The force that is applied to move the
load is called the effort force. The resistance arm is the part of the lever from the fulcrum
to the load. The longer the effort arm the easier it is to lift a load.
All levers can move heavy objects with small effort forces. First-class levers have
a fulcrum between the effort force and the load. A see-saw is a first class lever. In a
second-class lever the load is found between the effort force and the fulcrum. A
wheelbarrow is a second-class lever. In a third class lever, like a broom or a rake, the
effort force is between the load and the fulcrum.
A sloping surface that is used to raise a load is called an inclined plane. An
inclined plane decreases the force used to move an object by increasing the distance.
A pulley has a wheel and axle built in it. Pulleys change the direction of the work
and use gravity to make it easier to lift.
Wedges are used to split things. The wheel is the most widely used of all
The technological problem solving method is the
process used to solve a technology based problem.
Redesign and Gather
There are six steps in the technological problem Communicate Information
solving method. the Solution
A simulation is a way to model a process or product Test and Evaluate Solutions
without using the real thing. A system model is often the Solution
used to better understand how a system works. A
system is a combination of parts that work together to Implement
achieve a desired goal. A system has inputs, the Solution
processes, outputs, feedback and resources.