Final answer:
A tractor jackknife is the occurrence when the drive wheels take over the front wheels, causing the rear of the tractor to swing out. It happens when the rear wheels lose traction while the driver wheels still have traction.
Step-by-step explanation:
Tractor Jackknife
A tractor jackknife will occur when the drive wheels attempt to take over the front wheels, causing the rear of the tractor to swing out. This happens in situations where the rear wheels lose traction, while the drive wheels still have traction, leading to an uncontrolled movement of the rear end of the tractor.
To prevent a tractor jackknife, drivers should be cautious when driving on slippery roads or during sudden braking. Maintaining proper tire grip and adjusting driving techniques in adverse conditions, such as reducing speed, can also help avoid jackknifing.