1.    Classify machines.

    2.    Define mechanical advantage and efficiency.

    3.    Calculate the mechanical advantage and efficiency of machines.




A machine is a device that makes work easier.  A hammer, bicycle ramp,  and scissors are all examples of simple machines

There are always 2 forces involved in machines.

 Since there are 2 types of forces, there are 2 types of work.

Although machines can make work easier, they do not multiply work.

            WI = WO or FE * dE = FR * dR

 The work output can never be greater than the work input.

 Mechanical Advantage:

Mechanical advantage is equal to the number of times a machine multiplies the effort force.

If the MA is > 1, the machine multiplies force.

If the MA is = 1, the machine changes the direction of the force.

If the MA is < 1, the machine increases the distance or speed of an object.



 Efficiency is the comparison of work output to work input.

What is the major reason that the work output would be less than the work input?


                    The less friction a machine has, the higher its efficiency and work output.