WHEEL AND AXLE
• This is a simple machine.
• It consists of a wheel rigidly attached to a rod (called axle). When one rotates the wheel, the axle also rotates.
Figure 64: A train has wheel and axle attached to it
• Wheels help people do work in two ways.
• If we turn a large wheel fixed to an axle, the axle will also turn.
• We can turn something heavy, by spinning a large wheel attached to an axle that is attached to the heavy thing. That's how a pencil sharpener works.
• We can use a lot of force to turn the axle, and that will spin the wheels really fast. For example: cars
• The crank is used to raise a bucket of water from a well.
Figure 65: Crank
Figure 66: Ice cream maker, rotary dial telephone, phonograph
Figure 67: Skates, Doorknob
Figure 68: Stern wheeler of riverboat, navigation spinning wheels, barbecue
Figure 69: Windmill, bicycle
Figure 70: Animal cart, scooter
Figure 71: Steering wheel of ship, a wagon