Mechanical

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Mechanical

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Presentation Transcript

1. Mechanical Resistance

2. Friction Two solid objects sliding against each other. Drag The backwards drag of a solid object moving forward through a fluid. Two main causes

3. Cause of Friction • The hills and valleys of 2 objects acting upon each other.

4. Causes Cont. • Friction varies with the weight, normal force, pull, and force of friction on an object. • Objects are considered to be in equilibrium if the weight and normal force are = in size and opposite in directions.

5. Forces acting on an object

6. Wet Friction Adding lubricants to reduce the frictional forces between parts. Examples Rolling Friction Adding rolling parts to an object to reduce frictional forces between parts. Examples Ways of Reducing Friction Oil, grease, water, etc. wheels, ball bearings, etc.

7. How lubricants work • Separates surfaces • Places friction on lubricant Picture here

8. How rolling friction works • Surfaces don’t scrape together as much • Frictional Force is always less than sliding friction. Picture here

9. Static Initial force used to start moving an object. Kinetic Force used to keep an object in motion 2 Modes of Friction Static > Kinetic

10. Drag • Produced by a fluid moving over a solid object. • Fluids can be a liquid or a gas • Acts just like a lubricant in its movement • Causes turbulence on the solid object • Increases in a linear pattern to a point • picture

11. Ways of Reducing Drag • Streamlining • Creating a more aerodynamic solid object to reduce turbulence • picture