Simple Machines:

Objectives:

    1.    Identify the six simple machines.

    2.    Explain how each simple machine works

    3.    Calculate the mechanical advantage for each simple machine.

Resources:

    www.uark.edu/depts/aeedhp/agscience/simpmach.htm

Notes:

Simple Machines:

There are six simple machines:

  1. Inclined Plane

  2. Wedge

  3. Screw

  4. Lever

  5. Pulley

  6. Wheel and axle

 

Inclined Plane:

An inclined plane is a slanted surface used to raise an object.  It reduces the force required to move an object by increasing the distance of movement.

The height will always be shorter than the length.

(dots.physics.orst.edu/.../ inclined_plane_orig.gif)


Wedges and Screws:

A wedge is simply an inclined plane that moves.

A screw is an inclined plane wrapped around a cylinder.

 

(em-ntserver.unl.edu/NEGAHBAN/ EM223/note16/IMG00006.GIF)

Lever:

A lever is a bar that is free to move about a pivot point when a FE is applied to it.

 

1st class levers:

 

2nd Class levers:

                                                      

3rd Class levers:

   Mechanical Advantage of a lever:

               MA = FR/ FE or effort arm length / resistance arm length

 Pulleys:

A pulley is either a belt, chain, or rope around a wheel.

A pulley attached to a wall or ceiling is a fixed pulley

 A movable pulley is hung on a rope so that it moves with the FE.

 

     Mechanical Advantage of a Pulley:

            The MA can be estimated by adding the lengths of rope below the top pulley.

Wheel and Axle:

    Mechanical Advantage of a lever:   

        The MA = the radius of the wheel / radius of the axle


 

Compound Machines:

Are a combination of 2 or more simple machines.

 Cars, bikes, watch, Nearly everything that we can think of is made from simple machines.


How many simple machines can you see?