Answer:
Gravitational force
Explanation:
When ball is placed on the slope and slightly disturbed then ball will roll down the slope with increasing speed.
This increasing speed or acceleration of ball is due to the component of weight of ball which is along the inclined plane.
As shown in the FBD the component of weight perpendicular to inclined plane is used to counterbalance the normal force while other component of weight parallel to the inclined plane is accelerating the ball down the plane
So here we can write
[tex]mgsin\theta = ma[/tex]
so here
[tex]a = gsin\theta[/tex]
so ball is accelerating due to gravitational force
