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Unregistered
05-28-2006, 10:40 AM
Can a force have a magnitude measured in newtons? in pounds?...how about kilograms? Is kilograms both weight and mass on Earth?

When given a problem or situation to solve, should I
convert kilograms to pounds?
convert pounds to newtons?
convert kilograms to newtons?

Robert Fogt
05-30-2006, 04:36 PM
Kilograms is a unit of mass only, and pounds is a unit of force only. Technically you cant convert directly between them.

But, kilogram-force (kgf) is equal to the gravitational force on a mass of 1 kilogram. You can convert kilogram-force to pounds, since a pound is the gravitational force on a mass of 1 pound.

Similarly, a pound-mass can be converted to and from kilograms.

Units of force:
pound
kilogram-force
Newton

Units of mass:
pound-mass
kilogram

The difference between force and mass is absolutely the most confusing thing about traditional weight systems. On Earth, the difference is moot, so its my thoughts to generally ignore the difference.

I think that if you are doing something where the difference between force and mass is important, then you know about the difference between force and mass. If you know about the difference then the conversion pages will not screw you up.

Unregistered
08-12-2006, 09:07 PM
Can a force have a magnitude measured in newtons? in pounds?...how about kilograms? Is kilograms both weight and mass on Earth?

When given a problem or situation to solve, should I
convert kilograms to pounds?
convert pounds to newtons?
convert kilograms to newtons?

pls inform that 45kilogram mean how much pounds ?

Robert Fogt
08-13-2006, 04:06 PM
On Earth,

45 kilogram = 99.208 pound

Unregistered
10-22-2006, 07:03 PM
How many kilograms is 280 pounds?

Robert Fogt
10-23-2006, 05:02 AM
280 pound = 127 kilogram

You can do that on the Weight/Mass conversion page.
http://www.onlineconversion.com/weight_common.htm

Unregistered
01-11-2007, 04:12 AM
pls inform that 45kilogram mean how much pounds ?
what is main differance between kg and kgf

Robert Fogt
01-11-2007, 07:40 AM
kg is kilogram, a unit of mass.

kgf is kilogram-force, a unit of weight. It is the amount of force the Earth exerts on the mass of 1 kilogram.

While on Earth, 1 kilogram = 1 kilogram-force. Though technically a kilogram and a kilogram-force are different units and you cant directly convert between them, same with kilogram and pound. But while on Earth the difference does not matter so I usually tell people not to worry about it.

Its the most confusing part of traditional mass and weight systems. Scientists need to worry about it, but for the average joe its just there to confuse.

Unregistered
03-20-2007, 03:44 PM
Then how many newtons are in a kilogram?

Unregistered
04-30-2007, 07:04 PM
you have to consider gravity for what I think you are getting at, F=MA therefore 1 newton = 1kg * 9.81m/s on earth. Only works for things static, pushing towards earth's center.

Unregistered
05-05-2007, 03:26 AM
uhh... actually from F=Ma, 1 Kilogram * 9.8 m/s^2 (gravity) = 9.8 Newtons of force...
so 1 kilo exerts 9.8 Newtons of force on earth. 1 Newton is approximately equal to 100 grams on earth.

Leopold Plumtree
05-05-2007, 07:42 PM
The difference between force and mass is absolutely the most confusing thing about traditional weight systems.

This could be made somewhat easier by g = 1, but retaining the second as a time unit would mean a basic length unit of 9.80665 m, 32.174 ft.

That way, gravitational and absolute force units would be equal. :D

Unregistered
06-19-2007, 05:53 PM
How do I convert Kilograms to Newtons?

Unregistered
06-19-2007, 09:08 PM
Then how many newtons are in a kilogram?
my problem is calculate the wt2.5kg into newtons and what is the weight in pounds

Unregistered
09-15-2007, 03:04 PM
20 pounds is how many newtons?

Leopold Plumtree
09-15-2007, 04:19 PM
How do I convert Kilograms to Newtons?

Well, to convert kilogram-force (that is, the force required to accelerate a mass of one kilogram at a rate of 9.80665 m/s²), just multiply kg by 9.80665 (9.8 or 9.81 will do).

my problem is calculate the wt2.5kg into newtons and what is the weight in pounds

2.5 kgf ~ 24.5 N ~ 5.5 lbf

20 pounds is how many newtons?

20 lbf ~ 89 N

All the above values are based on earth's gravity. For this stuff, I won't bother with things like apparent weight and buoyancy in air, etc. ;)

Unregistered
10-03-2007, 12:45 PM
What is the buoyancy force on an object which displaces 560 kg of water?

and About how many pounds is this?

Leopold Plumtree
10-03-2007, 03:24 PM
What is the buoyancy force on an object which displaces 560 kg of water?

560 kgf

and About how many pounds is this?

1235 lbf

Unregistered
11-15-2007, 06:18 PM
20 pounds is how many newtons?
89 newtons

steacoon
10-03-2008, 07:47 AM
how do you go about converting Newtons to pounds?
take for example.. How many pounds is 300 Newtons?
If I have been doing this correctly;
(assuming I weigh exactly 190 lbs)

my mass is 8.61 x 10^1 Kg

my weight is 8.4378 x 10^2 N

and 900 N = 9.18 x 10^1 Kg

JohnS
10-03-2008, 12:01 PM
how do you go about converting Newtons to pounds?
take for example.. How many pounds is 300 Newtons?
If I have been doing this correctly;
(assuming I weigh exactly 190 lbs)

my mass is 8.61 x 10^1 Kg

my weight is 8.4378 x 10^2 N

and 900 N = 9.18 x 10^1 Kg

You are doing it basically correctly. However you can convert directly between newtons and pounds-force
1 lbf = 4.448222 N (from NIST SP811)

NOTE: 1 lbm = 0.453 592 37 kg exactly, per NIST definition of the pound (mass), but 0.4536 kg/lbm is accurate enough for any commercial purpose.

I would like to comment on converting between kilograms and newtons. At the risk of confusing you, standard gravity is indeed 9.80665 N = 9.80665 kg·m/s² as an adopted standard value. However, in structural analysis, falling bodies, etc, it introduces unnecessary precision as actual gravity varies about ±0.5% at sea level between the equator and the poles, more if you concsider mountain elevations, etc. If four or five significant figures are really needed, you have to know actual local gravity, which depends on latitude, elevation above sea level, and local geoidal variation..

Unregistered
03-02-2009, 02:29 PM
How many kilograms is 15 pounds?

JohnS
03-02-2009, 04:27 PM
How many kilograms is 15 pounds?

A pound is legally defined in the US as 0.45359237 kg
so 6.80388555 kg. (6.8 kg is probably good enough)

Unregistered
06-24-2009, 02:01 AM
Dear All,

may be this is a silly question, but i still not find a satisfied answer untill now.

why does Pounds have an acronym as lbs ?

thank you

robin
Jakarta,Indonesia

JohnS
06-24-2009, 03:54 AM
Dear All,

may be this is a silly question, but i still not find a satisfied answer untill now.

why does Pounds have an acronym as lbs ?

thank you

robin
Jakarta,Indonesia

Wikipedia says:
"The abbreviation lb comes from the Latin word libra, meaning "scales, balances",[1] which also described a Roman unit similar to the pound."

Unregistered
09-30-2009, 09:04 PM
what is 1 kilogram converted to newtons

JohnS
10-01-2009, 03:47 AM
what is 1 kilogram converted to newtons

The force of standard gravity acting on a 1 kg mass is 9.80665 N. Real gravity varies from this somewhat depending on latitude and altitude.

Unregistered
11-10-2009, 10:36 AM
pls inform that 45kilogram mean how much pounds ?

can you tell me what one kilogram is equal to in pounds

JohnS
11-10-2009, 11:19 AM
can you tell me what one kilogram is equal to in pounds

The pound is legally defined as 0.453 592 37 kg exactly.
Therefore 2.209 493 722 lb is about 1 kg.

Unregistered
08-02-2010, 02:38 AM
Can you please explain to me how you calculate kilograms to pounds

hildegard
08-02-2010, 02:42 AM
Calculate the following Kilograms into pounds please: 63 kg

JohnS
08-02-2010, 04:15 AM
Can you please explain to me how you calculate kilograms to pounds

The pound is legally defined as 0.453 592 37 kg exactly, in the US.
(Yes, we are really metric, pounds, feet, etc. are just declared fractions of metric units, since 1893.)

kilograms x 1 lb/0.453 592 37 kg = pounds

pounds x 0.453 592 37 kg/1 lb = kilograms

These will be exact to as many digits as the math is carried; however, the result should be rounded to about the same number of significant figures as the starting number. If you don't need full accuracy, you could round the conversion too, but use at least one more digit than you expect to carry in final result (guard digit).

Unregistered
07-15-2011, 09:27 PM
Thank you for the precise nature of your answer. I don't want the answers to things.. I want to know how to figure out the answer for myself.
And I LOVE that you are a supreme mumbler.... it is an exquisite talent to have. (sais by a fellow mumbler) Mumble mumble mumble....
--Scarlet

Well, to convert kilogram-force (that is, the force required to accelerate a mass of one kilogram at a rate of 9.80665 m/s²), just multiply kg by 9.80665 (9.8 or 9.81 will do).

2.5 kgf ~ 24.5 N ~ 5.5 lbf

20 lbf ~ 89 N

All the above values are based on earth's gravity. For this stuff, I won't bother with things like apparent weight and buoyancy in air, etc. ;)