AFOQT mech

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1. Force
something that can change the velocity of an object
2. friction
alway acts in the opposite reaction as to retard relative motion
3. sliding friction
when two objects are in close contact
4. spring scale
measures friction
5. newton
is a unti of force which is 4.45N=1lb
6. equilibruim
when an object is at equilibrium all forces acting on it are equal to zero
7. friction coefficient
depends more on the pressure between two surfaces rather than velocity
8. viscious drag
when a solid mass passes thru a liquid, gas or air vicous drag will occur. Viscous drag will increase as speed increases.

• - aerodynamic shapes come in to play
• -properties of the fluid also come into play
9. Weight
weight is equal to MG; mass x gravity
10. elastic recoil
when you applhy pressure on a solid object, that object will bend but also push back with a force equal to one exerted on it.
11. tension
tension can be measured by cutting a rope and introducing a spring scale
12. buoyancy
buoyancy acts in an upward direction on anything submerged in a liquid or gas.
13. Sinking
An object with a weight greater than the booyancy of the fluid it is in will sink.
14. forces
forces exist only in pairs
15. there are six simple machines
• these are
• 1. lever
• 2. incline plane
• 3. pulley
• 4. wedge
• 5. wheel and axle
• 6. screw
16. Work
work is the force applied over a distance
Output ratio to inout ratio of work produced by a machine
18. Work
whenever a force moves something over a distance. W=FxD
19. Newton
Force required to move 1 kilogram one meter in one second.

1kg x m/s
20. Mecahnical Advantage Formula
MA = Fl/Fe = load/effort
21. TCos theta
the force that actually produces horizontal movement when a force is appled at an angle.
22. Machine Efficiency
ME= Wout/Win = work put out / work put in
23. Vector
a Force with both magnitude and direction
24. Lever
FeDe = FlDl

• MA= Fl/Dl
• MA = Re/Rl
25. Lever types
• there are 3 types.
• class 1- fulcrum between effort and load; dolly

class 2- Fulcrum on one end, with load between; wheel barrow, nutcracker

class 3- Effort in the middle of load and fulcrum; fisherman, tongs
26. Incline Plane
plane set at and angle

MA = lenght / height

• Woutput = load x height
• Win= Force x lenght of ramp
27. Wedge
A double inclined plane that moves to exert a force along the lenght of its sides to push two objects apart

-knife, ax, chisel
28. Wheel and Axle
wheel and axle
29. Screw
can be thought of as an inclined plane with a wedge wrapped around a cylinder.

forces are applied perpendicular to the groove
30. Pulley
the pulley uses the principle of applying force over a longer distance. It also uses tension in the rope or cable.
31. MA of Pulley
De = Dl x supporting strands

E = Load / number of strands

W = F x D
32. Hydraulic Jacks
liquids are nearly incompressible.

MA = Al / Ae

Aii / Ai = Di / Dii

• Aii = diameter of larger circle
• Ai = smaller
• Di= Vertical distance of smaller
• Dii=Larger one
33. Gears
MA = # of teeth in load gear / # of teeth in effort gear
34. Power
• 1 ft-lb/s = 550 hp
• 746 joules = 1 hp
 Author: Anonymous ID: 166619 Card Set: AFOQT mech Updated: 2012-08-20 01:51:40 Tags: afoqt Folders: Description: afoqt Show Answers: