What is kilogram-force (kgf)?
Kilogram-force (kgf) is a unit of force based on standard gravity.
1 kgf is the force on a 1-kilogram mass at standard gravity, (g_0 = 9.80665\ \text{m/s}^2).
That means (1\ \text{kgf} = 9.80665\ \text{N}).
What is a poundal (pdl)?
A poundal (pdl) is a unit of force in the foot-pound-second (FPS) system.
It’s the force needed to accelerate a 1-pound mass at (1\ \text{ft/s}^2).
In metric terms, (1\ \text{pdl} \approx 0.138255\ \text{N}).
What is the conversion factor from kilogram-force to poundals?
The key conversion is:
- (1\ \text{kgf} \approx 70.9316\ \text{pdl})
This comes from converting kgf to newtons, then newtons to poundals.
How do you convert kgf to poundals?
Use this formula:
- (\text{pdl} = \text{kgf} \times 70.9316)
Example:
- (2\ \text{kgf} \approx 2 \times 70.9316 = 141.8632\ \text{pdl})
How do you convert poundals to kgf?
Use the reverse formula:
- (\text{kgf} = \text{pdl} \div 70.9316)
Example:
- (100\ \text{pdl} \approx 100 \div 70.9316 = 1.4098\ \text{kgf})
Why does the kgf to poundal conversion use standard gravity?
Kilogram-force is tied to standard gravity, not measured mass alone.
It assumes (g_0 = 9.80665\ \text{m/s}^2). If a different gravity value is used, the force in kgf changes.
Is kilogram-force a unit of weight or force?
kgf is a unit of force. People often use it to talk about weight, since weight is a force caused by gravity.
Mass stays the same; weight (force) changes with gravity.
What’s the difference between poundals (pdl) and pounds-force (lbf)?
Both are force units, but they are defined in different ways:
- Poundal (pdl) is based on accelerating 1 lbm at (1\ \text{ft/s}^2).
- Pound-force (lbf) is tied to standard gravity.
A useful link between them is:
- (1\ \text{lbf} = 32.174049\ \text{pdl})
Can I convert kgf to poundals using newtons?
Yes. It’s a clean two-step path:
- (1\ \text{kgf} = 9.80665\ \text{N})
- (1\ \text{N} \approx 7.23301\ \text{pdl})
So:
- (\text{pdl} = \text{kgf} \times 9.80665 \times 7.23301)
- This simplifies to (\text{pdl} \approx \text{kgf} \times 70.9316)
How many poundals are in 0.5 kgf?
Use (\text{pdl} = \text{kgf} \times 70.9316):
- (0.5\ \text{kgf} \approx 0.5 \times 70.9316 = 35.4658\ \text{pdl})
How should I round kgf to poundals results?
Rounding depends on your use:
- For quick estimates, 1 kgf ≈ 70.93 pdl works well.
- For tighter work, keep more digits (70.9316 pdl per kgf).
- Match the number of decimal places to your input accuracy.
Are kgf and poundals used in modern engineering?
Newtons (N) and pounds-force (lbf) show up more often today.
Kilogram-force and poundals still appear in older texts, some lab notes, and mixed-unit work.