You need to be more specific about the configuration. Is a single axle straight truck, a tandem axle straight truck, a tandem axle straight truck with additional lift axles, a tractor trailer...?
What type of truck and trailer? For all I know, you could be talking about a Ford F650 and a single axle utility trailer. If you're referring to Class 8 vehicles, something like a single axle tractor towing a single axle trailer would be allowed an interstate GVW of 52,000 lbs.
There's no such thing as a one axle truck. There has to be a minimum of two axles. "Single axle" if a term referring to a truck with only a single drive axle, and doesn't count the steer axle. Same with "tandem axle", "tri axle", "quad axle", and "quint axle".
Those designations actually exclude the steer axle, and only count axles behind the steer axle, so what you're talking about would actually be a truck with two axles - a steer axle, and a single drive axle.
Gross 52,000 lbs
Depends on what type of truck it is. It could be a single axle truck, a tandem axle truck, a tractor-trailer. You'd have to narrow your question down a bit. Tare (empty) weights will be affected by make and model of the vehicle, frame length, construction of the body, etc.
Varies by frame length, material used for the body, whether or not it has additional tag axles, etc. You could be looking at anywhere from 16,000 - 18,000 lbs. for a single axle truck to somewhere between 24,000 - 28,000 for a quad axle truck.
It depends on number of axles , equipment carried single axle could be up to 48000 lbs tandem could be up to 80000lbs
The power unit has a steer axle, and only one drive axle.
Depends on what model truck it is. Generally speaking, you can expect the manufacturer to rate them at 26,000 lbs, in order to allow them to be sold as non-commercial vehicles. However, many of them (such as the Ford F750) come with 31,000 lb axles. The max allowable weight on a single axle truck is going to be 33,000 lbs., but anything over 26,000 requires a CDL.
The length from the middle of the steer wheels to the center point between the drive tandems (for a tandem truck) or center of the single drive axle (on a single axle truck).
In the vicinity of 22,000 - 25,000 lbs.