1. Lesson 3-4, An Introduction to Mechanical Technology
Engineering Design
Lesson 3-4, An Introduction to Mechanical Technology

2. Objectives Explain how mechanical systems enhance human capabilities
Describe the factors that affect a mechanical system’s efficiency
Analyze the functioning of the mechanical systems in the designed world
Apply engineering design process to solve a problem

3. Mechanical Technology
The assembly of mechanical components to produce, control, and transmit motion.

4. Common Components Levers Shafts Inclined planes Couplings Wedges
Cables
Wheels and axels
Bearings
Pulleys
Brakes
Screws
clutches
Gears
Cams
Linkages

5. Simple Controls Complex systems may have layers of controls
Some controls operate particular parts of the system, while others control other controls
Even the most fully automatic systems require human control at some point.

6. Performance Evaluations
Mechanical Advantage
To find the MA of a machine, you can divide the resistance force by the effort force. Most of the time the resistance force is the weight of the object in Newtons.
Efficiency
The resultant amount of work (output), divided by the amount of work put into the machine (input)

7. Scientific Concepts
Force: a push or pull exerted by one object on another
Motion: any physical movement or change in position or place
Energy: the ability to do work.
Work: the transfer of energy from one physical system to another, expressed as the product of a force and the distance through which it moves a body in the direction of the force
Work (foot-pounds or Newton-meters) = Force (pounds or Newtons) x Distance (feet or meters)

8. Scientific Concepts (cont)
Power: Force divided by time. Measured in foot-pounds, newton-meters, or watts.
Gravity: the natural tendency of objects with mass to attract each other.
Friction: a force that opposes the motion or intended motion of a body in contact with another body.