Lesson 2.3: First Class Levers

You learned in Lesson 2.1 that there are three types of levers.  You performed an experiment with the first type of lever in Lesson 2.2.  That type of lever is called a First Class Lever.  How can you tell if a lever is a first class lever? 

You must look at three things:

  • The location of the fulcrum

  • The location of the effort

  • The location of the load

For all the diagrams that represent levers,
  represents the effort,

    represents the load, and

   represents the fulcrum.

Here is a diagram of a first class lever.

Notice the fulcrum is between the effort and the load.  It does not matter which side the load and effort are on. It does not matter how far or close to the fulcrum the load and effort are. It does not matter how big the load and effort are. One thing must be true: the fulcrum must be between the effort and the load.  Simple, right?  Here are more first class levers.

Question 1. Which of the following are NOT first class levers?  Explain each case.

       

Check your answers with those that follow.

 

 

 

 

 

 

 

 

 

 

 

Answers to Questions:

Question 1. Which of the following are NOT first class levers?  Explain.

B is not a first class lever because the fulcrum is not between the effort and the load.
C is not a first class lever because the fulcrum is not between the effort and the load.
D is not a first class lever because the fulcrum is not between the effort and the load.

Notice that it makes no difference which way the effort, load, or fulcrum are oriented (pointing).

 


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