What is a poundal (pdl)?
A poundal (pdl) is a unit of force from the foot-pound-second (FPS) system. It’s defined as the force needed to accelerate a 1-pound mass at 1 foot per second squared.
What is kilogram-force (kgf)?
Kilogram-force (kgf) is a unit of force based on standard gravity. It equals the force that gravity applies to a 1-kilogram mass at standard gravity (9.80665 m/s²).
How do you convert poundals to kilogram-force?
Convert poundals to kilogram-force using this formula:
kgf = pdl × 0.000141233
This factor comes from the relationship between newtons, poundals, and standard gravity.
What is the conversion factor from poundals to kgf?
The standard conversion factor is:
1 pdl = 0.000141233 kgf
This value is based on standard gravity (g₀ = 9.80665 m/s²).
How many poundals are in 1 kilogram-force?
One kilogram-force equals about 7,079.46 poundals:
1 kgf = 7079.46 pdl
This is the inverse of the pdl-to-kgf conversion factor.
Why is kilogram-force different from kilograms?
Kilograms (kg) measure mass. Kilogram-force (kgf) measures force. On Earth, a 1 kg mass weighs about 1 kgf, but the units are not the same.
Why do poundals and kgf use different systems?
Poundals come from an older FPS system used in some physics work. Kilogram-force comes from a gravity-based metric unit used in engineering and load ratings. They can both describe force, but they start from different base definitions.
Does the pdl to kgf conversion depend on gravity?
The conversion to kilogram-force uses standard gravity by definition. That means the factor assumes 9.80665 m/s², not local gravity.
What is an easy mental check for pdl to kgf conversions?
Poundals are small compared to kilogram-force. A quick check:
- 10,000 pdl is about 1.41 kgf
If your result is much larger than that, re-check the math.
Can I convert poundals to newtons first, then to kgf?
Yes. This two-step method works well:
- N = pdl × 0.138255
- kgf = N ÷ 9.80665
It gives the same final result as using the direct factor.
What’s an example conversion from poundals to kilogram-force?
Example: Convert 5000 pdl to kgf.
kgf = 5000 × 0.000141233 = 0.706165 kgf
So, 5000 pdl ≈ 0.706 kgf.
When would someone use poundals to kgf conversion?
This conversion comes up when comparing older FPS-based force values with metric force ratings. It can be useful in mechanics problems, testing notes, and equipment specs that mix unit systems.