Levers

Third order levers

 

A third order lever is one which has the effort between the fulcrum and the load.

 
Such levers do not have good mechanical advantage. In fact they have mechanical disadvantage. The effort is closer to the fulcrum than the load. The effort is always greater than the load. However, one advantage of such levers is that the distance moved by the load is greater than the distance moved by the effort.

 

 

 Cranes such as the one on the left are examples of third order levers. As you can see the effort is between the load, at the top, and the fulcrum. The advantage of this lever system is that the load moves through a greater distance than the effort. This is desirable when the crane needs to lift loads high above the ground.

 

Tweezers are another example of a third order lever.

Look at the image on the left. Identify the fulcrum, load and effort.
Is the arm an example of a third order lever? Explain.

Now that you have studied levers and hopefully hydraulics try constructing

Hydraulicus.
Hydraulicus can be purchased from Dynamic Science Education.

Check out the HomePage for this web site under "Products".

This is a great activity combining the knowledge you have gained with its practical application.

Try the exercises for Hydraulicus
Continue with velocity ratios

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