Using Levers and Electric Motors

Often we need to physically move an object.  Levers have been used in construction for  thousands of years!  The concepts of a lever also applies to pulleys, gears and gear boxes.  There are three kinds of levers.  They are classified as 1st Class, 2nd Class and 3rd Class.  Using a lever sometimes gives "mechanical advantage". The concept of mechanical advantage allows for a very small force to produce a larger force!  Only 1st and 2nd Class levers provide a mechanical ( force ) advantage.

    Please complete the tasks below.

  • This is an example of a 1st Class lever.  If the force is applied at the longer end of the lever, the shorter end force is greater!
  • There is a disadvantage to this kind of lever, as it requires a large movement that would take up a lot of space.
  
  • Using a lever is not always possible in a STEM project, as they do require more space in the construction structure.
  • This is a picture of a hand tool that uses the principles of a 1st Class lever
  • This kind of tool is being replaced by an electric motor and a gear box.
  • Levers are an example of mechanical control systems.  These systems are often replace by electrical control systems that use motors.
  • The electrical motor is attached to a lever with fewer linkage connections.
  • An example of a control system with complicated electrical and mechanical control systems is a toy helicopter.

 

Tasks and Activities

  1. Give an example of a "Third Class Lever"  (Hint - search Google)
  2. What is your definition of "mechanical advantage"?  Please use your own words.
  3. Think about your own STEM project.  Are you using a lever?  Why/Why not?
  4. Give a mechanical reason that a quadcopter is simpler than a helicopter? ( Hint -- think about a project with a lot of levers! )
  5. Electric gear boxes and hydraulic pumps are increasingly used to replace levers.  Why? ( Hint! -- Think about the size of the machine )

Don't forget to email your responses to Mr. Widmer by the end of this week.  Keep a copy of that email in your Google Docs folder. 

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