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From: glird on 31 Jul 2010 20:52 In the equation F = ma, F is a vector, denoting a force. (A "vector" is a line whose length denotes a quantity and whose direction is that in which the quantity is acting. A "force" is a net pressure measured independently of the area of application. A "net pressure" is the average amount of pressure in a given direction.) "Metrical pressure", generally called simply "pressure", is the dimension that measures physical pressure in terms of area of application. The difference between force and metrical pressure is that force is a net pressure measured independently of area of application, and metrical pressure is pressure per unit area independently of whether or not it is a net pressure (a vector) or a uniform pressure (a scalar). (A "scalar" denotes the magnitude of a local quantity, regardless of its direction.)
From: Sam Wormley on 31 Jul 2010 22:44 On 7/31/10 7:52 PM, glird wrote: > In the equation F = ma, F is a vector, denoting a force. (A > "vector" is a line whose length denotes a quantity and whose direction > is that in which the quantity is acting. A "force" is a net pressure > measured independently of the area of application. A "net pressure" is > the average amount of pressure in a given direction.) Pressure is the force over an area applied to an object in a direction perpendicular to the surface. http://en.wikipedia.org/wiki/Pressure#Definition
From: Igor on 1 Aug 2010 13:31 glird wrote: > In the equation F = ma, F is a vector, denoting a force. (A > "vector" is a line whose length denotes a quantity and whose direction > is that in which the quantity is acting. A vector is not a line. > A "force" is a net pressure > measured independently of the area of application. Force is not pressure.
From: NoEinstein on 1 Aug 2010 20:00 On Jul 31, 8:52 pm, glird <gl...(a)aol.com> wrote: > In the equation F = ma, F is a vector, denoting a force. (A > "vector" is a line whose length denotes a quantity and whose direction > is that in which the quantity is acting. A "force" is a net pressure > measured independently of the area of application. A "net pressure" is > the average amount of pressure in a given direction.) > "Metrical pressure", generally called simply "pressure", is the > dimension that measures physical pressure in terms of area of > application. > The difference between force and metrical pressure is that force is > a net pressure measured independently of area of application, and > metrical pressure is pressure per unit area independently of whether > or not it is a net pressure (a vector) or a uniform pressure (a > scalar). (A "scalar" denotes the magnitude of a local quantity, > regardless of its direction.) Dear glird: You are correct and won't offend any structural engineers who deal with the effects of forces all the time. Keep stating simple truths; those are rare on sci.physics. NoEinstein
From: NoEinstein on 1 Aug 2010 20:06
On Jul 31, 10:44 pm, Sam Wormley <sworml...(a)gmail.com> wrote: > On 7/31/10 7:52 PM, glird wrote: > > > In the equation F = ma, F is a vector, denoting a force. (A > > "vector" is a line whose length denotes a quantity and whose direction > > is that in which the quantity is acting. A "force" is a net pressure > > measured independently of the area of application. A "net pressure" is > > the average amount of pressure in a given direction.) > > Pressure is the force over an area applied to an object in a > direction perpendicular to the surface. > http://en.wikipedia.org/wiki/Pressure#Definition Dear Sam: Applying forces perpendicular is a CASE not a requirement of the term pressure. Example: Suppose a car traveling 35 mph strikes a concrete wall at a 15 degree angle. The wall experiences a pressure, but the force isn't perpendicular. Quit being a pedant, Sam. Glird knows a heck of a lot more than you. NoEinstein |