* Gravity: The primary force acting on the ball is gravity. Gravity pulls the ball downwards, causing it to speed up as it rolls down the incline.

* Component of Gravity: On an incline, gravity can be broken down into two components: one perpendicular to the incline (which is balanced by the normal force of the plane) and one parallel to the incline. This parallel component is the force that actually causes the ball to accelerate down the slope.

Why might it *seem* like the ball is decelerating?

* Friction: Friction, especially if the incline is rough, can oppose the motion of the ball, causing it to slow down over time. However, friction is a force that *opposes* motion, not the cause of deceleration itself.

* Rolling Resistance: As the ball rolls, there's some energy loss due to the deformation of the ball and the surface. This also contributes to a slight slowing down effect.

In summary: The ball accelerates down an inclined plane due to the force of gravity. Friction and rolling resistance can *reduce* this acceleration, but they don't cause the ball to decelerate (slow down) in the sense of going against the direction of motion.