Lb as measure of force

[Wolverine79]

In Ergdata, Average Force and Peak Force are measured in "Lb". For what is LB an abbreviation? Pounds is not a measure of force, so I assume it is not just pounds.

Also, I don't see where Lbs are used anywhere in the PM5, so I have no way to assess how good/bad are the Average Force and Peak Force figures I produce. Would it be more useful for Ergdata to provide max watts and average watts?

Thanks.

[Citroen]

It must be pound feet (LbF), on my metric Android phone it shows as "kg" (which is an awkward way to write Kg), so I'm equally puzzled. A sensible ISO unit like a Newton (N) would make more sense.

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[jsarche]

Having grown up in the Imperial system, I can say for sure that "lb" is an abbreviation for pound. It stands for the Latin word "libra."

Anyway, I've been wondering about that force measurement as well. I had been thinking that for a stroke that generates, say 120 pounds of force, it's the equivalent of lifting 120 pounds up from the ground. But that seems overly simplistic. Right? Anybody know?

[DavidA]

In Ergdata, Average Force and Peak Force are measured in "Lb". For what is LB an abbreviation? Pounds is not a measure of force, so I assume it is not just pounds.

Also, I don't see where Lbs are used anywhere in the PM5, so I have no way to assess how good/bad are the Average Force and Peak Force figures I produce. Would it be more useful for Ergdata to provide max watts and average watts?

Thanks.

It is pounds. Pounds is a measure of force.

David

[DavidA]

It must be pound feet (LbF), on my metric Android phone it shows as "kg" (which is an awkward way to write Kg), so I'm equally puzzled. A sensible ISO unit like a Newton (N) would make more sense.

Send feedback on the Play Store or Apple iTunes as appropriate.

kg is the correct abbreviation of kilogram. Kg is incorrect.
I don't know why it would show as kg on your metric phone, as kg is mass, and lb and N are force.

David

[Nomath]

lbs and kg are measures of mass. In ordinary life we experience mass mostly by its weight, which is a force.
A mass of 1 kg is what a scale shows as a weight of 1 kg, but physically it is the force of 1 kg mass pulled by the standard gravity acceleration (9.8 m/sec²) = 9.8 Newton (abbreviated N).
To indicate that a scale measures a force, the weight is preferably expressed as 1 kgf (kilogram-force).
The force associated with the mass of 1 lb is 1 lbf which equals about 4.45 N.

[Ombrax]

English units are super confusing when it comes to mass vs weight, but in general usage lb = pounds = force.

However, sometimes lbf = pounds force, and lb = pounds mass, which imo is a mess.

https://en.wikipedia.org/wiki/English_Engineering_units

The simplest solution is to use SI units if you have any choice in the matter.

And don't forget slugs and mugs and poundals too...

[Citroen]

English units ...

Curiously, we don't use that stuff in England - engineering is done in metric here. They're chiefly "American units" these days and those American units don't match the long time deprecated "English units" in all cases. You are in a group of three with Burma and Liberia in America.

[mict450]

In my former occupation, metric units are used exclusively. However, for personal use, I'm more comfortable with "American units". Thank goodness for the little conversion app on my phone that will translate for me!!

[jamesg]

In Ergdata, Average Force and Peak Force are measured in "Lb".

You can in Ergdata switch to kg if you wish. Go to the settings page and scroll down a few items to "Weight Units".

[Mortie31]

Force is mass x acceleration so the PM must be measuring both.
A newton is the force required to give a mass of 1 kilogram (1 kg) an acceleration of 1 meter per second per second (1 m/s2).
1 N is equivalent to 1 kg-m/s2.
A poundal is the force required to give a mass of 1 pound (1 lb) an acceleration of 1 foot per second per second (1 ft/s2). 1 poundal equals 0.1382 newtons.
So the units are Interchangeable by a simple calculation

[Ombrax]

Force is mass x acceleration so the PM must be measuring both.

Not to be pedantic about it, but given that we're talking about a rotary system, I bet that they measure the angular motion of the flywheel, and since they know the inertia, can calculate torque and related stuff and what the aero drag on the flywheel must be. Then, they back-calculate what the force applied at the handle must have been to result in what they measured at the flywheel.

[Mortie31]

Force is mass x acceleration so the PM must be measuring both.

Not to be pedantic about it, but given that we're talking about a rotary system, I bet that they measure the angular motion of the flywheel, and since they know the inertia, can calculate torque and related stuff and what the aero drag on the flywheel must be. Then, they back-calculate what the force applied at the handle must have been to result in what they measured at the flywheel.

I think your very likely to be correct

[Ombrax]

Curiously, we don't use that stuff in England - engineering is done in metric here. They're chiefly "American units" these days and those American units don't match the long time deprecated "English units" in all cases. You are in a group of three with Burma and Liberia in America.

In a related matter, I bet you didn't know that Americans have two feet.

In fact, most Americans don't know this: https://nyti.ms/2Q1p8H7