Blowing My Load
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Every object continues in a state of rest or of uniform motion until it is compelled by a force to change its state of rest or motion.
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The change in motion of an object is proportional to the net magnitude of the combination of the applied forces, and takes place along the straight line in which the ombination of the applied forces acts (sometimes stated as: F = MA, or force = mass x acceleration).
The equation "F = MA" is a simplification of Newton's second law, but it has extreme significance. It means that the force required to accelerate an object is equal to the mass of the object multiplied by the desired acceleration. This simple equation forms the basis for determining the loads applied to objects as the result of motion ("dynamics").
4/30
For every action, there is an equal and opposite reaction. In other words, when two objects exert forces on each other, the forces are equal in magnitude, opposite in direction, and collinear.
5/30
A PRESSURE is the result of a FORCE being applied to a specific cross-sectional area, and is defined as FORCE per unit AREA, as in POUNDS per SQUARE INCH. For example, if a downward FORCE of 1000 pounds is applied evenly to a square plate of steel which measures 2" by 2" (4 square inches of area), then the PRESSURE applied to that block (Force per unit AREA) is determined by dividing the FORCE (1000 pounds) by the AREA (4 square inches), which is 250 pounds per square inch ("psi").
If the same 1000 pound FORCE was applied to a plate which measured 2" x 4" (8 square inches), then the PRESSURE would be reduced to 125 psi because the area of the plate doubled. The same force is being applied over a greater area, resulting in a LOWER force per unit area.
Taking it a step further, suppose you have a hydraulic cylinder with a 1/2" diameter piston. The area of that piston = diameter x diameter x 0.785, or in this case, 0.5 x 0.5 x 0.785 = 0.196 square inches. Now, if you apply 1000 pounds to the rod of that cylinder, the 1000 pound FORCE is applied by the rod to the piston, which acts against the oil in the cylinder to produce a pressure in the oil of 5102 (1000 / 0.196 = 5102) psi. If that oil is routed through some tubing to another hydraulic cylinder which has a 2.5 inch diameter piston, then the 5102 psi will be applied to the 4.91 square inch piston (2.5 x.2.5 x .785 = 4.91) and results in a 25, 050 pound force being available at the end of the rod on that cylinder.
6/30
FRICTION is an especially interesting example of a force. It is the resistance to motion which takes place when one body is moved upon another. Friction is generally defined as "that force which acts between two bodies at their surface of contact, so as to resist their sliding on each other".
7/30
elocity is defined as the rate at which the position of a body changes with respect to some reference. Typically, the reference is time, and we are all familiar with everyday expressions of velocity (speed), such as miles-per hour, feet-per-second, revolutions per minute, furlongs-per-fortnight, etc.
In addition to time, another common reference variable is rotation, or angular position. For example, the change in the position of a piston with respect to the angular movement of the crankshaft is a convenient way to study piston motion. Similarly, the change in the position of a cam follower with respect to the angular position of the camshaft is a convenient way to study valvetrain motion.
The term velocity technically refers to a vector quantity, meaning that it has both magnitude and direction. The "speed" of an object is the measure of how fast the object is moving, without regard for the direction. Saying that a car is travelling 60 MPH is a statement of its speed, whereas saying it is travelling 60 MPH North defines its velocity.
8/30
Angular velocity is the measure of rotational distance something moves in a specified amount of time. It is typically expressed in units such as revolutions-per-minute (RPM) and degrees-per-second.
For many engineering calculations, it is necessary to express angular units as radians instead of degrees, and angular velocity in units of radians-per-second, rather than degrees-per-second or revolutions per minute (RPM). The explanation of "why" requires more math than is appropriate here, but suffice it to say that it is necessary in order to make the numbers work out right.
A radian is an angular measurement equal to approximately 57.3 degrees. It is defined as the angle formed by an arc on the circumference of a circle, the length of which is equal to the radius of that circle. Since the circumference of a circle is the radius times 2π, then obviously the value of a radian is the angle 360° divided by 2π, or 57.29578 degrees.
9/30
Part of a 4 part set
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3/4
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4/4
13/30
Acceleration is the measurement of how quickly the velocity of an object is changing, usually with respect to time. If you measure the velocity of an object at a particular time (Time1), then again at a subsequent time (Time2), then the average acceleration which the object has experienced will be:
Acceleration = (Velocity2 - Velocity1) / (Time2-Time1)
Clearly, the longer the period of time over which the measurements are taken, the more that value becomes an average, and the less will be known about the instantaneous acceleration of the object.
14/30
However, acceleration (and velocity as well) need not be expressed with respect to time. For example, the acceleration value typically used in camshaft lobe design is inches-per-degree-per-degree or inches-per-degree2 . This value is the acceleration which a cam lobe applies to the cam follower it is driving. In order to calculate the forces a cam applies to its mating components, the cam lobe angular velocity with respect to time must be known. Using that value, the lobe acceleration value can then be converted into inches-per-second-per-second, from which the forces are then calculated. In 2004, for some undiscernible, but most certainly politically-correct, reason, the cam design community apparently switched to metric units { velocity in mm/deg and lobe acceleration in mm/deg2 }.
15/30
Suppose the engine of your car stalled while you were in line to exit from a flat, level parking lot. You try several times to restart it, but it just won't start.
Since you are a considerate person, you decide to push your car out of the way of the people behind you. You get out and go round back and begin to push on the car. Suppose also that you are a fairly strong person, so you exert a horizontal force of 100 pounds on the rear of the car. The car doesn’t move. But you are also a persistent person, so you continue to push on the car for two whole minutes, exerting the same 100 pounds of force. The car still won’t move. Although you will probably be quite tired, you will have done NO WORK.
WHY? Because WORK is defined as a FORCE operating through a DISTANCE. The car didn’t move, so although there was FORCE, there was no MOTION.
Now you get smart and release the parking brake, and, having recovered from your previous 2-minute exercise in futility, you again push the car with the same constant 100 pound force. This time the car moves, and you push it for another two minutes. It travels 165 feet during that two minutes of effort. In that case, you will have produced 16,500 foot-pounds of WORK (100 pounds of force x 165 feet of distance = 16,500 foot-pounds).
16/30
Later that day, you are working in your shop. You need to install a 3-inch long spring into a 2-inch space. The nature of this particular spring is that it takes 600 pounds of force to compress it one inch (the "spring rate" = 600 pounds per inch).
Using a lever-operated spring compressor, you pull on the lever with a force of 100 pounds and you move the lever 6 inches, causing the compressor to squeeze the spring and shorten it by 1 inch. The spring is now pushing on the compressor with a force of 600 pounds. You have stored the WORK you did on the compressor lever (100 pounds x 6 inch = 600 inch-pounds) in the spring, in the form of ENERGY (600 pounds x 1 inch = 600 inch-pounds).
ENERGY is defined as the CAPACITY of a body to do WORK, by virtue of the position or condition of the body.
17/30
Now suppose there is a 150-pound plate of steel on your bench, resting on four blocks which are 2 inches tall (so the space between the bottom of the plate and the bench is 2 inches). You install the compressed spring into that space and locate it at exactly the CG of the plate, and release the spring compressor.
The spring will lift the steel plate 3/4 of an inch, so the spring has done WORK on the plate, thereby releasing some of the ENERGY stored in the spring.
There are many different forms of energy. There are a few which are of particular interest with respect to powerplants: kinetic energy (the energy contained in a body by virtue of its velocity), potential energy (the energy contained in a body by virtue of its position), chemical energy (energy which can be released by a chemical reaction, such as combustion), and heat energy (energy which can be used to make machines operate).
18/30
POWER is defined as the rate of doing WORK, or WORK per unit TIME.
POWER (the rate of doing WORK) is dependent on TORQUE and RPM.
TORQUE and RPM are the MEASURED quantities of engine output.
POWER is CALCULATED from torque and RPM, by the following equation:
HP = Torque x RPM ÷ 5252
19/30
I'm unclear as to whether League hentai is /h/ or /aco/ appropriate.
On the one hand the source material is American, on the other hand the /h/ rules say /h/ is for all stuff done 'in the hentai style', while /aco/ is implicitly for that which is not done 'in the hentai style'.
I would say it probably doesn't matter, but there is no more anal-retentive or pedantic being in the universe than a nerd that's just blown his load, and there's no shortage of such creatures here.
20/30
Engines (and motors) produce POWER by providing a ROTATING SHAFT which can exert a given amount of TORQUE on a load at a given RPM. The amount of TORQUE the engine can exert usually varies with RPM.
TORQUE is defined as a FORCE around a given point, applied at a RADIUS from that point. Note that the unit of TORQUE is one pound-foot (often misstated), while the unit of WORK is one foot-pound.
21/30
POWER is the measure of how much WORK can be done in a specified TIME. In the example earlier on Work and Energy, the guy pushing the car did 16,500 foot-pounds of WORK. If he did that work in two minutes, he would have produced 8250 foot-pounds per minute of POWER (165 feet x 100 pounds ÷ 2 minutes).
22/30
In the same way that one ton is a large amount of weight (by definition, 2000 pounds), one horsepower is a large amount of power. The definition of one horsepower is 33,000 foot-pounds per minute. The power which the guy produced by pushing his car across the lot (8250 foot-pounds-per-minute) equals ¼ horsepower (8,250 ÷ 33,000).
23/30
Stress is a value which describes the amount of load carried by each unit of cross sectional area of a component.
The loads which produce tensile and compressive stresses are acting perpendicular to the areas on which they act. Tensile and compressive stresses are often referred to as normal stresses. Here, "normal" is not a behavioral term, but a geometric one, which, in this context means "acting perpendicular to" a particular area or plane.
When your prick hits the back of her vaginal wall and you keep pressing anyway, your mansteak is under compressive stress. When you're pulling out and a suction sensation is pulling your pecker back in, your tallywhacker is experiencing tensile stress. Both of these stresses are 'normal', presumably because your lame ass is in the missionary position you boring and uncreative vanilla twatwaffle.
24/30
Forces which act parallel to the areas resisting them are known as shear forces, and produce shear stress in the elements which carry those loads.
Let's say you pull out just enough so that the tip of your Fleshsicle remains inside. You slide to your left, she slides to her left. Your prick is now under shear stress. This was a bad idea.
It is important to note that the shear stress capacity of most metallic materials is considerably less than the tensile or compressive capacities.
25/30
Bending Stress occurs when a component is loaded by forces which, instead of trying to stretch or shrink the component, are trying to bend it. Those bending forces generate a combination of tensile and compressive stress in the load-carrying components, known as bending stress.
26/30
Strain is the measure of how much a material deforms when a load is applied to it, expressed in inches of deformation per inch of material length. For example, if a 1/2" diameter shaft supporting a 10,000 pound load is 12" long, it will stretch about 0.020" (20 thousandths) from its unloaded length, which you can measure. The strain is the measured deflection (0.020) divided by the length of the shaft, or 0.020 ÷ 12 = 0.00167 inches per inch.
27/30
Suppose you measure a specimen which has no load applied to it. Then you apply a load to the specimen, then release the load and measure the specimen again. If you find that it has returned to its original length, then the specimen experienced elastic deformation when it stretched under the load.
Most materials are elastic. That is, if you apply a load to the material, it will deform in some way, by an amount which is proportional to the load. When you remove the load, the material will return to its original shape, as long as the load wasn't too large. The deformation might be too small to measure, but it still occurs.
If, after the load is released, you can measure some permanent deformation in the specimen, (the specimen does not return to its original length), then the material has been stressed beyond its elastic limit and has experienced plastic deformation.
28/30
There are two basic values which characterize the strength of a metal. Each of those values is a stress level at which a particular event occurs.
The stress level at which a material no longer behaves elastically, but instead experiences a small permanent (plastic) deformation is known as the Yield Stress (YS), (also known as the proportional limit). That is the stress level at which the elastic limit of the material has been exceeded.
29/30
The second interesting value is called the Ultimate Tensile Stress (UTS). It is the stress value at which the material will break under the influence of pure tensile stress.
30/30
It has been known for a long time that the presence of irregularities or discontinuities in a part (holes, rapid changes in diameter, shoulders, grooves, notches, etc.) significantly increases the value of the actual stress which occurs in a part when compared to the stress value calculated based on the cross section of the part. These increases in stress, called stress concentrations, occur in the immediate vicinity of the discontinuity.
The ratio of the actual stress to the calculated stress is known as a stress concentration factor. The magnitude of stress concentration factors can be 3, 4, or more depending on the severity of the particular discontinuity.
This phenomenon can be demonstrated in tests. There is a large body of accumulated data relating the physical characteristics of various types of discontinuities to the increase in observed stress they cause. There are several books which present the methods to calculate these factors. One of the most accepted works on this subject is Peterson's Stress Concentration Factors. Some FEA systems have incorporated the effect of discontinuities into their calculations.
There are also several accepted methods to diminish the stress-increasing effect of discontinuities, including tapers, large fillet radii, radiused undercuts, and gentle discontinuities surrounding a necessarily abrupt one.
