what does it mean to jackknife a trailer
Jackknifing Jackknifing refers to the folding of an articulated vehicle i.e. one towing a trailer, such that it resembles the acute angle of a folding pocket knife. If a vehicle towing a trailer skids, the trailer can push the towing vehicle from behind until it spins the vehicle around and faces backwards. This may be caused by equipment failure, improper braking, or adverse road conditions such as an icy road surface. In extreme circumstances, a driver may attempt to jackknife the vehicle deliberately in order to halt it following brake failure. A jackknife event of a heavy vehicle can be fatal to the driver as the top of the cab can be crushed or sliced off as it swings round violently and tries to fold under the trailer.[citation needed]
Donkey A male donkey or ass is called a jack, a female a jenny or jennet;[3][4][5] a young donkey is a foal.[5] Jack donkeys are often used to mate with female horses to produce mules; the biological "reciprocal" of a mule, from a stallion and jenny as its parents instead, is called a hinny.