What is a newton (N)?
A newton is the SI unit of force. It’s the force needed to speed up 1 kilogram of mass by 1 meter per second squared (1 m/s²). In short, 1 N = 1 kg·m/s².
What is a poundal (pdl)?
A poundal is a unit of force in the foot-pound-second (FPS) system. It’s the force needed to speed up 1 pound (lb) of mass by 1 foot per second squared (1 ft/s²). In short, 1 pdl = 1 lb·ft/s².
How do you convert newtons to poundals?
Use this conversion:
- 1 N = 7.23301385 pdl
- pdl = N × 7.23301385
This works because both units measure force, just in different base units.
How do you convert poundals to newtons?
Use the reverse conversion:
- 1 pdl = 0.138254954 N
- N = pdl × 0.138254954
What is the exact conversion factor from N to pdl?
The standard factor is:
If you need fewer decimals, you can round based on your accuracy needs.
Why is 1 newton equal to about 7.23 poundals?
A newton is based on kilograms and meters, while a poundal is based on pounds (mass) and feet. Since kilograms, pounds, meters, and feet don’t match in size, the same force turns into a different number. The 7.233 value comes from those base-unit relationships.
Is a poundal the same as a pound-force (lbf)?
No. A poundal (pdl) and pound-force (lbf) are different units.
- Poundal (pdl) uses pound-mass and acceleration (lb·ft/s²).
- Pound-force (lbf) is based on standard gravity.
A common relationship is:
- 1 lbf = 32.174049 pdl (using standard gravity)
When would you use poundals instead of newtons?
Poundals show up in older physics and engineering work that uses the FPS absolute system. Newtons are far more common today, but poundals still matter when you need to match a legacy formula, table, or textbook.
What’s a quick mental estimate for newtons to poundals?
For a rough estimate:
- Multiply newtons by 7.2 to get poundals.
Example:
How many poundals are in 10 newtons?
Using the standard factor:
- 10 N × 7.23301385 = 72.3301385 pdl
Rounded:
How many newtons are in 100 poundals?
Using the reverse factor:
- 100 pdl × 0.138254954 = 13.8254954 N
Rounded:
Does the N to pdl conversion depend on gravity?
No. Newtons and poundals are both force units defined by mass and acceleration. Gravity matters when you convert between mass and weight (like lbm to lbf), but not for N to pdl.
What units should I use for force in physics problems?
Use the unit system that matches the rest of your inputs.
- If your mass is in kg and distance in m, use newtons (N).
- If your mass is in lb and distance in ft, and you’re using the FPS absolute system, use poundals (pdl).
Mixing unit systems can cause mistakes, so keep everything consistent.