Automatic braking systems (ABS) on automobiles prevent the tires from locking by sensing when the tires stop spinning and then reducing the braking force until they begin to spin again. Knowing that an automobile equipped with ABS will (A) always stop in a shorter distance (B) stop in shorter distance on dry pavement but not on wet pavement (C) stop in about the same distance (D) always stop in a longer distance than an automobile that stops by locking the tires.

							
(B) stop in shorter distance on dry pavement but not on wet pavement.
Automatic braking system on automobiles prevents tires from locking and reduces the skidding effect. The sensors are used to compare the rotational speed of a tire against the other, and a control mechanism is implemented by the hydraulic braking system thereafter.
If the rotational speed of the tire is slower relative to other tires, the hydraulic braking system reduces the braking force on tire, and its rotational speed increases thereby preventing skidding or locking effect. The reverse is done if the rotational speed of tire is found to be greater than the others.
Therefore, one would expect an automobile with ABS to stop in a shorter distance compared to an automobile without any ABS. However, one should also note that frictional forces on a wet pavement will be relatively lower when the tire is rolling as compared to when it is skidding . hus, in a situation when the braking system increases the rotational speed of tires on a wet surface, the skidding could take an automobile farther than it would be on an automobile with no ABS.
Thus, (B) is the correct option, and the rest are ruled out.