Who is liable when a human Uber gets in an accident today? Nobody.
Hmm, I'm curious: are you just trolling, or do you really not know how liability works? Because it's usually not nobody. Actually it's **never** nobody. It's almost always the driver (or at least *a* driver, if multiple cars are involved). That's why insurance of some kind is mandatory to drive cars on the road: otherwise the driver might be liable for payouts they might not be able to afford. Sometimes it's a defect in the car, in which case, yes, the manufacturer is liable, but that usually requires a pretty serious design flaw. Otherwise mechanical failure is usually considered the fault of the owner for failing to maintain the car properly.
Weight is a vector quantity
Ehh, you *can* define it that way, but it's often defined as a scalar quantity W=mg, were m and g are both scalars, and *always* used that way in common parlance (and scientific parlance rarely considers weight). Even the most anal physicist, if asked their weight, would only give it in vector notation if they were trying to make a point.
"It ain't so much the things we don't know that get us in trouble. It's the things we know that ain't so." -- Artemus Ward aka Charles Farrar Brown