I have absolutly seen people who are unskilled at picking up and moving boxes. It’s not a task with a high skill floor, or a particularily high skill ceiling, but it exists.

And somehow my company has been uniformly capable of identifying and hiring these people.

Seems like a lot of math they could argue.

Fine them daily gross income for each identified product for each day since the last inspection with no findings.

Make them beg for more frequent inspections.

The meter is defined by the distance light travels in a specific fraction of a second. It may have been initially defined by a rough estimate but it (and all metric measurements) are now fixed to universal constants.

Also the foot is currently defined exclusively as 0.3048 meters, so you are already using metric.

Sound is transferred through a medium literally as a wave. When you get right down to the core of it, the wave requires movement within the medium to transmit.

So it might help to conceptualize it not as “Liquid cannot move faster than the speed of sound in it’s medium” but more like “The speed of sound in a liquid medium is defined by the speed at which energy can propagate in that system, which includes motion.”