$10,000 a year
2.69 per mile
No, they are belt driven. That's how they operate.
Depends on what type of tractor and trailer you had in mind. For a farm tractor pulling a trailer, it's usually a pintle on the tractor which is run through a clevice on the trailer. For road going vehicles, the fifth wheel trailers are often used, where a trailer kingpin will be inserted and locked into a fifth wheel on the vehicle. In the case of an 18 wheeler, air lines will connect from the tractor to the trailer to operate the trailer's air brake system.
About £200
Depending on the make, the average length of a tractor is 22 feet. A standard trailer is 53 feet. The combined average length of the vehicle is 70 feet.
Around $60,000, and unless you work for a company you can't buy a separate trailer. $135,000 for a fullsize tractor, $72,000 for a reefer trailer.
The average tractor trailer holds almost 300 gallons of gas! I am unsure of if you were speaking of a tractor trailer or a tractor for cutting the lawn.
Bigger than average
The average length of a standard tractor trailer is 70 feet in all, the trailer itself being 53 feet in length. Most flatbed trailers are 48 feet long.
Four to nine MPG, depending on a number of factors. It's pretty much the same with any tractor trailer.
This site looks promising http://www.nexttruckonline.com/ they sell trucks, tractor trailers and accessories/maintenance items that you would need for your tractor trailer.
Whatever the company pays.