Simple Machines Physical Science Chapter 13 Section 2
- Slides: 18
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 thirdclass 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: a) Drill bit b) Skateboard ramp c) 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.