Final answer:
The primary problem associated with front-wheel lock up when braking on a slippery surface is the loss of control and the inability to steer the vehicle effectively.
Step-by-step explanation:
The primary problem associated with front-wheel lock up when braking on a slippery surface is the loss of control and the inability to steer the vehicle effectively.
When the front wheels lock up, the car will skid in a straight line regardless of the driver's turning inputs, making it difficult to avoid obstacles or navigate tight turns.
This is primarily due to the lack of traction between the tires and the road, resulting in a loss of dynamic friction.