Final answer:
The two forces acting on a ball when it is kept on the ground are the weight of the ball due to gravity and the normal force exerted by the ground.
Step-by-step explanation:
When a ball is kept on the ground, it experiences two primary forces: the weight of the ball due to gravity, and the normal force exerted by the ground. The weight of the ball is the force due to Earth's gravitational field acting upon the mass of the ball, pulling it downward. In contrast, the normal force is the reaction force exerted by the ground that supports the ball and acts perpendicularly to the surface of the ground. These two forces generally balance each other out when the ball is at rest on a level surface, resulting in no net force and, therefore, no acceleration of the ball in the vertical direction.