The primary determinant for the acceleration of an object is the net force acting on it, as described by Newton's second law of motion. This law states that the acceleration of an object is directly proportional to the net force and inversely proportional to its mass. In formula terms, this is expressed as \( F = ma \), where \( F \) represents the net force, \( m \) is the mass, and \( a \) is the acceleration. Consequently, increasing the net force on an object will result in greater acceleration, while increasing its mass will decrease acceleration for a given force.