First Semester Flashcards
Work
/ft
Work * distance
2nd rule of machines
Machine enable us to amplify speed at the expense of force
5 simple/ancient machines
Lever Pulley Wheel & axel Inclined plane/wedge Screw
Chains
Won’t slip compared to vbelts
Load is based on lubrication (we use type 1 lube)
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110 v
Newton’s 3rd Law
Every action has equal opposite reaction
Friction
Resistance that keeps 2 objects from slipping and moving past each other
Wedge IMA
Length(diag)/height
3rd rule of machines
Can’t do both rules at same time
Inertia
Tendency of an object to continue moving or not
Unit for torque
Ft/#’s
Torque
Twisting motion about an axis
2nd Class Lever
Load located between fulcrum and force
Ratio of 1:2
Work
Force * distance
Prime mover
Source of input power to the system
-might be motor, engine, gravity, freshman
Parallel
Parallel lines
Screw effort force
Resist force/(IMA*efficiency)
Machine rules
Machine must have more power than load
Drive system/transmission must have greater power capacity than the motor
1st class lever
Fulcrum in between load and force
Ratio of 1
Efficiency
AMA/IMA
EMF
Electromotive force
Photoelectric
Thermoelectric
Mechanical magnetic
Piezoelectric friction
Acceleration
Rate @ which we change speed/sec
Minimum belt contact
150 degrees so you have friction
Cheapest gears to maintenance
Spur gears
-noisy
1 HP = ____ #/1 Ft/ 1 Sec
550#
West VirginiA
Watts = volts • amps
Hots in 220 load if coming from 220 source
2
Pulley IMA
of lines supporting load, 4:1, 3:1, etc
Hots in 110
1 hot
1 neutral
Wedge AMA
IMA * efficiency (given)
Moment arm * force
Torque
Helical gears
Converts more torque at a time
- more expensive
- introduces lateral force
Belt advantages
Inexpensive in relation to gearboxes
Require little maintenance, no grease or oil
Can tolerate high misalignment
Slipping can be advantageous
Wheel Axle IMA
Rw/Ra
Radius of wheel/radius of axle
IMA
Displacement Effort/ Displacement resistance = IMA
3rd Class Lever
Force located between fulcrum and load
Differential chain hoist IMA
2R/R-r
R = big radius
r = small radius
4 parts of useful electrical circuit
Source of EMF
conductor
Load
Control
How many watts in 1 HP
746 Watts
Series
Erasing line after first stop to first on
Bevel gears
90 degree similar to spur gears
Inexpensive
Newton’s 1st Law
Object at rest will stay at rest, object in motion will stay in motion unless acted on by outside force
1st rule of machines
Enable us to amplify force at expense of distance/speed
Angle of repose
Angle before impending motion
7 reasons why we automate
- Weight
- Repeat
- Money
- Speed
- Complexity
- Accuracy
- Education
F=MA
Amount of force to overcome the inertia of an object
Screw IMA
Circumference of handle/Pitch
=23.14r/Pitch
Newton’s 2nd Law
When force applied to object, object will move in direction of force
Point of impending motion
When force of the effort overcomes static friction
RPM formula
(Distance/time)*12
/drum circumference
*60
AMA
Fr/Fe=AMA
Herring bone fear
No lateral force cause 2 of them
Can do twice the work
-more expensive
Pulley AMA
load/force
