Final answer:
The ladder exhibits circular motion as the top slips down because it moves in a circular path around the pivot point at the bottom.
Step-by-step explanation:
When a ladder 25 feet long is leaning against a wall and the top of the ladder slips down the wall, the motion it exhibits is circular motion. This is because a point on the ladder such as the top, as it slips, will follow a circular path around the point where the bottom of the ladder contacts the ground, which acts as the pivot. It is not linear motion since the ladder does not move along a straight path; oscillatory motion implies a repetitive back-and-forth movement that does not occur in this scenario; and projectile motion involves an object moving under the influence of gravity after being projected into the air, which does not accurately describe the ladder slipping down a wall.