[a9h74j]

Depends upon what you set out to measure. lbs is specifically a unit of force. kg is specifically a unit of mass. It is a category error to equate these as measures, although (in many places) an everyday convention to do so on Earth.

IIRC the English unit for mass is the slug. If the tecnical limit is 70lbs or so, that is must technically be read as lbs force -- aka force of gravity which varies with location.

[dragonwriter]

> lbs is specifically a unit of force

Incorrect. The avoirdupois pound (lb) is historically a unit reflecting the long conflation of mass and force, but the modern unit of that name is expressly a mass unit that is a derived unit of the kilogram. The corresponding unit for force is the pound-force, (lbf).

[zmgsabst]

Wikipedia lists it as a unit of mass — as defined by the amount that exerts a certain force.

https://en.wikipedia.org/wiki/Pound_(mass)

The pound unit of force is abbreviated ‘lbf’.

https://en.wikipedia.org/wiki/Pound_(force)

[rzzzt]

Kilopond or kilogram-force is the force with which a 1 kg object is pushing on its base: https://en.wikipedia.org/wiki/Kilogram-force

[jrochkind1]

you could really take USPS for a ride by shipping something to Venus!