Inclined Plane

• An inclined plane allows an object to be moved up or down gradually with less force.Medioimages/Photodisc/Photodisc/Getty Images
  
  A ramp is another term used for inclined planes. It is simply a flat surface with one end higher than the other. An object can be pushed up the ramp instead of lifted straight up, so you need a smaller force to overcome gravity with a ramp. If the slope of the plane is gentler, a smaller force will be necessary. Inclined planes can also be used to move a load to lower ground at a gradual pace instead of straight down.
  
  

Wedge

• Wedges are two inclined planes placed together so their lower ends meet to form a narrow point. The main use for a wedge is to split things. If a force is applied at the top end, then the pointed end will be pushed down into the material, pushing it apart. If the two inclined planes have steeper slopes, it will take less force to cut through materials.
  
  

Lever

• A lever is a rigid bar with a point called a fulcrum on which it can turn, allowing one side to rise while the other lowers, and allowing the points on the bar to follow the path of a circle. If a downward force is applied on one side it will transfer the force upward on the other side.
  
  

Wheel and Axle

• The wheel is any type of circle, and the axle is a point at the center of the circle that allows it to spin while staying in place. If a force is used to spin the wheel, it can be transferred to any spot on the outside of the wheel. For example, if the wheel touches the ground, a force used to spin it will be transferred to push off the ground.
  
  

Screw

• In a screw an inclined plane is wrapped around a central cylinder. Any force used to turn the screw will move the inclined plane, and the inclined plane will exert this force by pushing up or down on the object. Twisting a screw into wood, for example, will pull the screw down into the wood tightly.
  
  

Pulley

• A pulley is a grooved wheel on an axle with a rope placed in the groove. A force applied downward on one side of the rope will pull up on the other side. In this way a pulley can be like a lever. Multiple pulleys can be put together to make a system to ease the work needed and redirect the force in different ways.