Professional Driving

Question 1

Define kinetic energy

Answer 1

KINETIC ENERGY is what causes the damage and injury during a collision. Any object that has weight and is moving has kinetic energy.

A moving vehicle must give up kinetic energy as it slows or stops.

The process of transferring kinetic energy from one body to another is what does the damage and bodily injury in a collision.

A vehicle gets more kinetic energy in one of two ways, increasing its weight, or increasing its speed.

If a moving vehicle has its weight doubled, it’s kinetic energy is doubled.

If the vehicle has it’s speed doubled, the kinetic energy is quadrupled. Thus quadrupling the distance it will take to come to a stop.

Kinetic energy is measured in a geometric progression.

Question 2

Define negative weight shift

Answer 2

Negative Weight Transfer

Front wheels break traction easier than rear wheels due to weight shift to the rear (under steer).

Less force needed to turn wheel: less response to rapid steering.

Question 3

Weight transfer when vehicle brake is jabbed

Answer 3

Positive Weight Transfer

Rear of vehicle breaks traction easily (over steer) especially on slick surface.

Much more weight on the front wheels of the vehicle when the brake pedal is jabbed.

More force needed to turn wheels.

Question 4

Define neutral steer

Answer 4

All Wheel Skid (Neutral Skid)

This skid occurs when both the front and rear tires of the vehicle follow the same radius around the curve. Neutral steer occurs when both the front and rear tires lose traction at the same time and moment. This is the most common skid and there is no control for steering. The vehicle goes in a straight line (center mass of travel).

Question 5

Correct way to correct an over-steer

Answer 5

Rear Wheel Skid (Over–steer)

This skid is caused by the rear tires loosing traction while the front tires are still turning. The vehicle tries to spin around 180 degrees. One cause of this skid is hard braking during a turn.

Rear Wheel Skid: Corrective Action

1. Get off the brakes and accelerator.
2. Then counter steer in the direction in the direction you want to travel to re-establish rolling friction.