The "tandem" part means it has two drive axles, although it is possible for a tandem truck to be a 6x2 vehicle, and have only one of those be a live axle.
It could be either. Tandem simply means that the power unit has two drive axles which operate in tandem. It's common in both articulated and straight trucks.
It sounds to me like you're describing a straight truck, rather than a semi-tractor. I'd need to know the model number before I gave you an answer... what you're describing could be either be a single or a tandem axle truck.
Five
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).
Who invented the Semi-truck?
If the semi truck knocked on the garbage truck, yes.
Depending on wheelbase, what kind of body is attached to it, etc., it could be anywhere from 13,000 lbs. and up. A daycab semi tractor with a single frame.. you'd be looking between 15,000 and 17,000 lbs. A tandem roll off with an empty 30 yard container and double frame construction, you're looking more in the vicinity of 33,000 lbs. The permitted gross weight for a tandem truck is 54,000 lbs.
A vehicle with 18 wheels is commonly known as a "semi-truck" or "tractor-trailer."
Semi-articulated
The total square footage inside a 53 foot semi trailer is about 3,400 square feet. This space can only be fully occupied if the semi truck and trailer weight combined is 80,000 pounds or less. Federal law regulates how much a loaded semi truck and trailer can weigh. There are also limits on axle weight to arrive at this total. It is 12,000 for steer tires, 34,000 for drives, and 34,000 for tandem axles.
There is no prefix in truck.
Tom Nelson invented the semi truck in 1945