1. An understanding of mechanical advantage and work helps in determining the efficiency of machines.
1.1. 2.1 Machines Make Work Easier
1.1.1. Mechanical Advantage:amount a machine can multiply force.
1.1.2. Input Force: force appllied to a machine.
1.1.3. Output Force: force a machine applies.
1.1.4. Speed Ratio: measure of how the speed of the object is effected by the machine.
1.1.5. Friction: force that opposes movement.
1.1.6. Efficiency: measurement of how well a device uses energy.
1.2. 2.2 The Science of Work
1.2.1. Work:
1.3. 2.3 The Big Movers- Hydraulics
1.3.1. Hydraulic System: system that uses liquid under pressure to move loads.
1.3.2. Pasals Law: the law that an external pressure applied to a fluid in a closed vessel is uniformly transmitted throughout the fluid.
1.3.3. Pressure:measure of the force applied in an area.
2. Science, society, and the enviorment are all important in the development of mechanical devices and other technology.
2.1. 3.1 Evaluating Mechanical Devices
2.1.1. Design: the phisical form of a device.
2.1.2. Function: what the device is supposed to do.
2.2. 3.2 Technology Develops Through Change
3. Machines are tools that help humans do work.
3.1. 1.1 Simple Machines- Meeting Human Needs
3.1.1. Machine:device that helps us do work
3.1.2. Simple Machine: tool or device made up of one basic machine.
3.1.3. Lever: simple machin with a plank that rotates on a fulcrum to lift an object.
3.1.4. Inclined Plane: simple machine made up of a board at angle to a flat surface.
3.1.5. Wedge:simplemachine that is forced into an object.
3.1.6. Screw:simple machine that is a cylinder with a spiral on the side.
3.1.7. Pulley:simple machine of a rope on a grooved wheel.
3.1.8. Wheel and Axle: simple machine made up of two wheels that turn together.
3.2. 1.2 The Complex Machine- A Mechanical Team
3.2.1. Complex Machine: system with many simple machines.
3.2.2. System: a group of parts that work together.
3.2.3. Subsystem: smaller group of parts within a complex machine.
3.2.4. Linkage: belt that transfers energy.
3.2.5. Gear pair of wheels with teeth.