Physical Science Chapter 13 Section 2 Simple Machines Physical Science Chapter 13 Section 2

What are Simple Machines? The lever, pulley, wheel and axle, inclined plane, wedge, and screw are simple machines. Can be broken down into the lever and inclined plane families.

The Lever Family Levers have a rigid arm that turns around a point called a fulcrum. A lever can increase the force without increasing the work done, because the output force will be exerted through a smaller distance.

The Lever Family Levers are divided into three classes depending on the locations of the fulcrum, input force, and output force.

The Lever Family First-class levers are the most common such as a claw hammer. Scissors are made of two first-class levers joined together.

The Lever Family Second-class levers include wheelbarrows, nutcrackers, and hinged doors.

The Lever Family The human elbow is an example of a third-class lever

The Lever Family Pulleys are modified levers.

The Lever Family A wheel and axle (a car’s steering wheel) is a type of lever that is connected to a shaft.

The Inclined Plane Family Inclined planes turn a small input force into a large output force. Which requires more force: lifting the piano directly into a van or rolling it up a ramp?

The Inclined Plane Family A wedge is a modified inclined plane. Using a wedge is like pushing a ramp instead of pushing something up the ramp.

The Inclined Pane Family A screw is an inclined plane wrapped around a cylinder.

Compound Machines Made of two or more simple machines.

Review #1 What are the six types of simple machines?

Review #2 Identify the type of simple machine represented by each of the following examples: Drill bit Skateboard ramp Boat oar

Review #3 How can a lever increase the force applied without changing the amount of work being done?

Review #4 Why would pulleys be in the lever family?

Review #5 Think of a compound machine that you use every day that were not shown in today’s slides. Identify the simple machines that make it up.