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  #21  
Old 02-02-2009, 09:03 AM
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Originally Posted by cojaro View Post
Static friction is the resistive force between an object and the surface against it GIVEN THAT the object is not in motion. Once the object is in motion, the friction force is known as kinetic (or dynamic) friction. The static friction force is usually greater than the kinetic friction force (ever notice it's harder to get a heavy object moving than it is to keep it moving?)

Weight, in English usage, is ambiguous. In common usage it's used to describe the "mass" of an object. However, in the scientific community, weight is something much different. For example, a kilogram is a unit of mass, and the weight of a 1kg object is simply the product of the mass and Earth's gravitational acceleration: w = m*g. In English units, this is a bit more complicated, as you have to convert from pound-mass (lbm) to pound-force (lbf) or throw the unit of slugs (1 slug = 1 (lbf*s^2)/ft) into the equation.

Education is learning. Enlightenment is a realization of a new perspective on a situation or of a new approach to a problem. One can lead to the other.

To anyone who takes the time to read this entire article, I encourage you to look up any and every term you do not fully understand.

I think you will find that kilogram is a force just like pounds. The only difference is the scale.(1 kg = 2.205 lb)
You can use m=w/g where weight is in pounds and the acceleration of gravity 32.16 ft/sec squared on earth averaged. (gravity does change with location on earth). Mass is merely the way to equalize weights btween various planets or any other place that the force called weight is measured.

Last edited by mahout; 02-02-2009 at 09:06 AM.
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  #22  
Old 02-02-2009, 10:45 AM
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Force Units
Newton [N, kg*g]
pound(-force) [lbf = 4.4482216152605 N]

Mass units
kilogram [kg]
pound(-mass) [lbm]
slug [slug = 32.17 lbm = (lbf*ft)/s^2]

As an engineer in training, I'm pretty sure I know the difference between weight and mass. No offense.

Last edited by cojaro; 02-02-2009 at 10:47 AM.
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  #23  
Old 02-02-2009, 04:51 PM
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Quote:
Originally Posted by cojaro View Post
Force Units
Newton [N, kg*g]
pound(-force) [lbf = 4.4482216152605 N]

Mass units
kilogram [kg]
pound(-mass) [lbm]
slug [slug = 32.17 lbm = (lbf*ft)/s^2]

As an engineer in training, I'm pretty sure I know the difference between weight and mass. No offense.

As a PhD ME and ChE with 50 years experience, no offense taken.
Pounds and kilograms are units of force. The only difference is 1 kg is 2.205 lb. Both have to be divided by the respective acceleration of gravity in their units for the location involved, metric or english, to get mass.
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  #24  
Old 02-02-2009, 05:56 PM
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Originally Posted by mahout View Post
As a PhD ME and ChE with 50 years experience, no offense taken.
Pounds and kilograms are units of force. The only difference is 1 kg is 2.205 lb. Both have to be divided by the respective acceleration of gravity in their units for the location involved, metric or english, to get mass.
PhD ME? I can't imagine the amount of math involved in getting that o_O

Do tell, if kg/g = mass, what units are used? I mean, if you're right, then all I've learned in Physics I, II, Thermodynamics and Statics is fundamentally incorrect! :O Even my TI89 says _lb*_g = _lbf. You must be yankin' my chain or something.
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  #25  
Old 02-02-2009, 08:25 PM
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Originally Posted by cojaro View Post
PhD ME? I can't imagine the amount of math involved in getting that o_O

Do tell, if kg/g = mass, what units are used? I mean, if you're right, then all I've learned in Physics I, II, Thermodynamics and Statics is fundamentally incorrect! :O Even my TI89 says _lb*_g = _lbf. You must be yankin' my chain or something.

Not at all. a measurement of mass includes the acceleration of its pull of gravity whether so stated or not, though usually the author includes the subscript m when mass is intended. It is primarily useful in physics where gravity is not as consistent as on earth. Force is just a vector magnitude expressed as pounds or kilograms.
Mass = force/acceleration and its units are always force/distance per sec per sec.
An object of one lbm has a weight of 32.16 lbf on earth and about 4 lbf on the moon. (memory says the moon has about 1/8 the gravity of the earth).
T189 is correct; pounds mass x acceleration = pounds force. You can calculate easily as long as you use consistent measurement scales.
Kg/m/sec/sec x m/sec/sec = kg as an example.
Did that help?
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  #26  
Old 02-02-2009, 08:51 PM
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Originally Posted by mahout View Post
Not at all. a measurement of mass includes the acceleration of its pull of gravity whether so stated or not, though usually the author includes the subscript m when mass is intended. It is primarily useful in physics where gravity is not as consistent as on earth. Force is just a vector magnitude expressed as pounds or kilograms.
Mass = force/acceleration and its units are always force/distance per sec per sec.
An object of one lbm has a weight of 32.16 lbf on earth and about 4 lbf on the moon. (memory says the moon has about 1/8 the gravity of the earth).
T189 is correct; pounds mass x acceleration = pounds force. You can calculate easily as long as you use consistent measurement scales.
Kg/m/sec/sec x m/sec/sec = kg as an example.
Did that help?
A bit. Maybe we're just seeing the same thing from different angles *shrug*
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  #27  
Old 02-05-2009, 06:11 PM
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Quote:
Originally Posted by cojaro View Post
Force Units
Newton [N, kg*g]
pound(-force) [lbf = 4.4482216152605 N]

Mass units
kilogram [kg]
pound(-mass) [lbm]
slug [slug = 32.17 lbm = (lbf*ft)/s^2]

As an engineer in training, I'm pretty sure I know the difference between weight and mass. No offense.
in a text book
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  #28  
Old 02-05-2009, 06:28 PM
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Quote:
Originally Posted by cojaro View Post
Static friction is the resistive force between an object and the surface against it GIVEN THAT the object is not in motion. Once the object is in motion, the friction force is known as kinetic (or dynamic) friction. The static friction force is usually greater than the kinetic friction force (ever notice it's harder to get a heavy object moving than it is to keep it moving?)

Weight, in English usage, is ambiguous. In common usage it's used to describe the "mass" of an object. However, in the scientific community, weight is something much different. For example, a kilogram is a unit of mass, and the weight of a 1kg object is simply the product of the mass and Earth's gravitational acceleration: w = m*g. In English units, this is a bit more complicated, as you have to convert from pound-mass (lbm) to pound-force (lbf) or throw the unit of slugs (1 slug = 1 (lbf*s^2)/ft) into the equation.

Education is learning. Enlightenment is a realization of a new perspective on a situation or of a new approach to a problem. One can lead to the other.

To anyone who takes the time to read this entire article, I encourage you to look up any and every term you do not fully understand.
u can quote me definitions all u want but u lack fundamental understanding
a non-skidding rotating tire (zero slip angle and not "burning out or locking the brakes") is only under STATIC friction NOT dynamic friction
mechanical "weight" is MASS!!!!!! stop spreading dumbness around
engineers would use the term MASS
u r merely in training and r not a professional engineer
do u get 100% or more (bonuses points) on all your assignments and exams?
thought so
(perfect gpa DOES NOT COUNT as 100%)
understanding is NOT the same as reprinting facts (that merely means that u r as smart as a photocopier or fax machine)
reprinting formulae from a grade 10 science text book does not make u look smart (why did u bother?)

study hard.......

no offense
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  #29  
Old 02-05-2009, 06:30 PM
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Quote:
Originally Posted by mahout View Post
I think you will find that kilogram is a force just like pounds. The only difference is the scale.(1 kg = 2.205 lb)
You can use m=w/g where weight is in pounds and the acceleration of gravity 32.16 ft/sec squared on earth averaged. (gravity does change with location on earth). Mass is merely the way to equalize weights btween various planets or any other place that the force called weight is measured.
an object has mass in space but no weight
do u really think mass is used for different planets?
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  #30  
Old 02-05-2009, 08:02 PM
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Originally Posted by TheImmortal View Post
u can quote me definitions all u want but u lack fundamental understanding
a non-skidding rotating tire (zero slip angle and not "burning out or locking the brakes") is only under STATIC friction NOT dynamic friction
Um, yeah, and? No one asked me what the friction force is for a "non-skidding rotating" (i.e. rolling) object.

Quote:
Originally Posted by TheImmortal View Post
mechanical "weight" is MASS!!!!!! stop spreading dumbness around
engineers would use the term MASS
u r merely in training and r not a professional engineer
do u get 100% or more (bonuses points) on all your assignments and exams?
thought so
(perfect gpa DOES NOT COUNT as 100%)
understanding is NOT the same as reprinting facts (that merely means that u r as smart as a photocopier or fax machine)
reprinting formulae from a grade 10 science text book does not make u look smart (why did u bother?)
Good job assuming I copied and pasted, because I didn't. The only thing I looked up was the relationship between a slug and a pound-force because, so far, I've only needed to use slugs in Thermodynamics (even in there, rarely.)
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  #31  
Old 01-11-2010, 10:46 PM
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nice info btw, this is what i'm looking for.
continue my reading to the 2nd part

thanks
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  #32  
Old 02-15-2010, 07:13 AM
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May I suggest the site: SuspensionCalculator to perform all suspension related calculations.

All feedback would be greatly appreciated
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  #33  
Old 04-08-2010, 10:54 AM
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rear sway bar mounting

I have a 2008 Fit DX. I want to reduce understeer by installing a rear sway bar. It will be secured to the control arms by bolts. The heads of these bolts will interfere with the lower spring mount rubber. I fear they'll pierce the rubber and cause metal- metal contact with the lower end of the spring.

Is this concern real, and what's the solution?

Thanks, Rick..............
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  #34  
Old 04-08-2010, 03:28 PM
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Originally Posted by Rick Roth View Post
I have a 2008 Fit DX. I want to reduce understeer by installing a rear sway bar. It will be secured to the control arms by bolts. The heads of these bolts will interfere with the lower spring mount rubber. I fear they'll pierce the rubber and cause metal- metal contact with the lower end of the spring.

Is this concern real, and what's the solution?

Thanks, Rick..............
that's because you need to change the hardware...
you will need button head screws instead, the reason why they don't include them first hand IMO is that the head is weaker in tension... but anyway with a RSB the screw should only suffer from shear stress...
check the FS section i think there's someone selling them...
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  #35  
Old 03-20-2015, 11:51 PM
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i don't have time to learn all this great stuff. I'm too busy.

i just need one of you experts to verify that i'll be better off with a Progress RSB on my 2012 base fit with 195/65/15 tires (1" larger diameter than stock tires)

also, will it cost me fuel economy? and how much all things being equal?
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  #36  
Old 03-21-2015, 12:15 AM
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Quote:
Originally Posted by cojaro View Post
Force Units
Newton [N, kg*g]
pound(-force) [lbf = 4.4482216152605 N]

Mass units
kilogram [kg]
pound(-mass) [lbm]
slug [slug = 32.17 lbm = (lbf*ft)/s^2]

As an engineer in training, I'm pretty sure I know the difference between weight and mass. No offense.
As an engineer with 3 degrees and 50 years experience, be assured that pounds and kilograms are both forces, the result of the units in weight, or force, of mass times acceleration., or mass = force/acceleration of the body on which its measured. it is indeed the way to equivalent weights on different bodies, such as the moon and earth. you may have noticed the astronauts on the moon could jump a lot higher there than on earth; the acceleration is a lot less on the moon than the earth.
no offense but pay attention in class.
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  #37  
Old 03-21-2015, 12:25 AM
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Originally Posted by cojaro View Post
PhD ME? I can't imagine the amount of math involved in getting that o_O

Do tell, if kg/g = mass, what units are used? I mean, if you're right, then all I've learned in Physics I, II, Thermodynamics and Statics is fundamentally incorrect! :O Even my TI89 says _lb*_g = _lbf. You must be yankin' my chain or something.
in english units: pounds and feet per second squared on the greater body
in metric units: kilograms and meters per second squared on the greater body.
on earth the acceleration of a body in a vacuum is 32.16 ft per second per second on earth. in metric units its 9.8 meters per second per second.
practically speaking there is a limit to the velocity as a result of the resistance of the falling body in air. so v = ac doesn't increase with time except in a vacuum; and in a vacuum there are also limitations thanks to Albert but not in our earthbound work.
if it helps add d = 1/2 at squared + original velocity x t.
then ask why integrated velocity increase with time isn't that simple.
as for lb x g is lb force, it misses. the lb force from a falling weight is the result of velocity * weight., or F w* at.
if it were w*g the lb force won't change and surely you know thats not true. Would you rather be hit by a baseball dropped from 5 feet or 25 feet?

Last edited by mahout; 03-21-2015 at 12:34 AM.
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  #38  
Old 03-21-2015, 12:39 AM
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Quote:
Originally Posted by space egg View Post
i don't have time to learn all this great stuff. I'm too busy.

i just need one of you experts to verify that i'll be better off with a Progress RSB on my 2012 base fit with 195/65/15 tires (1" larger diameter than stock tires)

also, will it cost me fuel economy? and how much all things being equal?

the rear antisway bar will reduce understeer but because of your higher center of gravity may reduce your cornering speed. as for mpg you've already done the damage with a bigger diameter and heavier tire unless you run at constant speeds all the time.
generally we lower the car by lower profile tires or springs and add the RSB or disconnect the front bar.
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  #39  
Old 03-21-2015, 12:44 AM
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Originally Posted by TheImmortal View Post
u can quote me definitions all u want but u lack fundamental understanding
a non-skidding rotating tire (zero slip angle and not "burning out or locking the brakes") is only under STATIC friction NOT dynamic friction
mechanical "weight" is MASS!!!!!! stop spreading dumbness around
engineers would use the term MASS
u r merely in training and r not a professional engineer
do u get 100% or more (bonuses points) on all your assignments and exams?
thought so
(perfect gpa DOES NOT COUNT as 100%)
understanding is NOT the same as reprinting facts (that merely means that u r as smart as a photocopier or fax machine)
reprinting formulae from a grade 10 science text book does not make u look smart (why did u bother?)

study hard.......

no offense

uh, if one of the surfaces is moving relative to the other its dynamic friction. its static only if both surfaces are stationary to each other.
mechanical weight is force, not mass.
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  #40  
Old 03-21-2015, 12:50 AM
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Originally Posted by TheImmortal View Post
an object has mass in space but no weight
do u really think mass is used for different planets?
an object in space is measured only by size and material; it really has no mass unless you compare it's force, or weight. one body to another body.
so yes, mass is used to measure forces on different bodies. knowing the mass on earth I can determine the force or weight it generates on mars, the moon, or the sun, however briefly.
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