I'm going through a physics exercise at high school level. A ball is dropped through a slide and when it reaches the bottom of the slide it will travel horizontally. Assuming there is no energy loss due to friction or air resistance draw a velocity time graph. I tried working it out, the answer on the book says that when the ball reaches the bottom of the slide it will start moving horizontally with a positive constant velocity. I'm a bit confused on the constant velocity part. When the ball is moving horizontally, it obviously has KE. And the fact that it has energy doesn't it mean that there is a force applied through a distance, and therefore it should accelerate? Many thanks in advance!