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Physics Definition of Tension
Tension is a contact force transmitted through a rope, string, wire or something similar when forces on opposite ends are pulling on it.
For example, a tire swing hanging from a tree causes tension in the rope holding it to the branch. The pull on the bottom of the rope comes from gravity, while the upwards pull is from the branch resisting the rope's tug.
Mathematically: Fg = Ft where Fg is the force of gravity, and Ft is the force of tension, both in newtons.
Recall that the force of gravity, Fg, is equal to an object's mass times the acceleration due to gravity g. So Fg = mg = Ft.
For a 10-kg tire, the force of tension would thus be Ft = 10 kg × 9.8 m/s2 = 98 N.
In the same scenario, where the rope connects with the tree branch there is also zero net force. At this end of the rope, however, the force of tension in the free-body diagram is directed downwards. However, the magnitude of the force of tension is the same: 98 N.
originally posted by: turbonium1
Once again, the reason objects don't go upward into the air, and fall down when in air, is due to their mass being greater than that of air. It's that simple.
Why do you think objects of greater mass than air would RISE UP into areas of lesser mass?
originally posted by: neutronflux
a reply to: turbonium1
He EXPLAINED that he never accounted for 'curvature'
And the Individual explained why.
Observations made at each station at exactly the same time, cancels the effects of curvature and refraction
Is that a false statement.
originally posted by: dragonridr
Your own quote proves you wrong he's explaining how you can avoid having to calculate Earth's curvature. Hes not claiming it doesn't exist!
here is his quote
Using short observation distances (25 m) equalized for backsight and foresight
Air below is denser than air above Air below is denser than air above, Line of sight is bent downward which Negates earth curvature error by 14%.
Now notice he said he used short observation distances namely 25 meters. So of course in 75 feet you don't have to concern yourself with earth curvature.
Then next he says your line of sight is bent downwards negating the curve by 14 percent on top of his short measurement.
See he's not saying it's not there he's telling you how to avoid calculating it as a surveyor. His solution was simply more measurements to avoid the math.
I find it funny you debunked yourself
originally posted by: OneBigMonkeyToo
a reply to: turbonium1
Is that before or after the bit that says 'How to eliminate errors due to curvature'?
It's better to say you don't know what causes the tides, or don;t know for sure what causes them, than to keep claiming 'lunar gravity' or whatever causes it, because that's complete BS. Even if 'gravity' DID exist, it doesn't work. Lies upon lies don't solve sh&(t, and never will.
I've not looked into the theory I mentioned in depth, but hope to soon, among other theories as well.
A column can buckle due to its own weight with no other direct forces acting on it, in a failure mode called self-buckling. In conventional column buckling problems, the self-weight is often neglected since it is assumed to be small when compared to the applied axial loads. However, when this assumption is not valid, it is important to take the self-buckling into account.
Elastic buckling of a "heavy" column i.e., column buckling under its own weight, was first investigated by Greenhill at 1881. He found that a free-standing, vertical column, with density
rho , Young's modulus
E, and cross-sectional area
A, will buckle under its own weight if its height exceeds a certain critical value:
[displaystyle l_[text[max]]approx left(7.8373,[frac [EI][rho gA]]right)^[frac ]]
g is the acceleration due to gravity,
I is the second moment of area of the beam cross section.
Types of errors in Levelling
Curvature and Refraction in Surveying and Leveling Through History. Old Books, etc.