What is a simple machine?
a machine that uses only one movement
List the 6 simple machines.
lever, inclined plane, wedge, screw, pulley, wheel and axle
Define mechanical advantage
the number of times the applied force is increased by a machine
Describe an ideal machine. Why is it an ideal machine?
A machine which there is no friction. This is an ideal machine because the work you do on a machine is equal to the work done by the machine.
Recall that work equals force times distance. How can you get more work, but use less force?
The distance of force must be increased.
What does friction do to some of the force used by a machine so that it is not used to do work?
Friction causes some of the input work to be changed into het, which cannot be used to do work.
What is a pulley?
A pulley is an object, like a wheel, that has a groove with a rope or cable running through it.
What can a pulley change and how can we use pulleys to increase work?
A pulley changes the direction of the input force. We can use pulleys to increase work by adding more.
What is a lever?
A lever is a rod or plank that pivots about a fixed point.
What is the pivot point of a lever called?
fulcrum
How many different classes of simple levers exist?
Three
What class levers increase the output force?
The first class and second class
What is a wheel and axel and how do we determine its mechanical advantage?
A wheel and axel is made of two round objects that are attached and rotate together about the same advantage. The mechanical advantage is calculated by dividing the wheel by the radius of the axle.
How do the lever, pulley, wheel and axle, and inclined plane make work easier?
They reduce the amount of force needed by increasing the distance to complete the required amount of work.
What is an inclined plane?
A sloped surface
How does the length of the ramp affect the force required to move an object?
The longer the ramp is, the less force it takes to move the object.