Lesson 3.3: Wheel and Axle

When you read the term "wheel and axle", the image that comes to mind is usually the wheels and axle of a car or a bicycle or your skateboard.  As a simple machine, the wheel and axle takes on many unusual forms.  Doorknobs, water taps, steering wheels, and even a screwdriver are examples of the wheel and axle. 

Read Turning and Turning: The Wheel and Axle on page 143 of your textbook. Then, respond to the following questions.

Question 1. What is the wheel and what is the axle on each of the following?

  1. doorknob

  2. screwdriver

  3. wrench turning a nut

  4. winch

  5. steering wheel of a car

Question 2. Here is a picture of two steering wheels.  The large steering wheel is from an older car, the small steering wheel is from a newer car.  Explain why the older steering wheel is so much larger than the newer steering wheel.

                   

Question 3. The picture of the adjustable wrench and the diagram of the winch do not have a wheel in them.  What is behaving as a wheel in these machines?

                                

Check your answers with those that follow.

 

 

 

 

 

 

 

 

 

 

 

Answers to Questions:

Question 1. What is the wheel and what is the axle on each of the following?

  1. doorknob - Wheel is the handle you turn, axle is shaft that goes through the door.

  2. screwdriver - Wheel is the handle and axle is the screwdriver end or the shaft.

  3. wrench turning a nut - Wheel is the wrench and axle is the nut on the bolt.

  4. winch - Wheel is the handle and axle is the roller.

  5. steering wheel of a car - Wheel is the steering wheel and axle is the shaft that is turned.

Question 2. Here is a picture of two steering wheels.  The large steering wheel is from an older car, the small steering wheel is from a newer car.  Explain why the older steering wheel is so much larger than the newer steering wheel.

The steering wheel from the old car has to be bigger because the car did not have power steering.  The large wheel made it easier to steer the car.  The newer steering wheel is much smaller because the car has power steering, which requires very little strength to steer the car.

Question 3. The picture of the adjustable wrench and the diagram of the winch do not have a wheel in them.  What is behaving as a wheel in these machines?

The handle of each behaves as the wheel in these machines.  The handle rotates about the axle just as a wheel would.                      


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