When a force of 3.0N is applied to a block on a flat surface, the velocity of the block increases over time while the acceleration remains constant. This means that the velocity graph will show a linear increase, indicating that the block is speeding up. The acceleration graph will be a horizontal line, reflecting the constant acceleration due to the applied force. The misconception that the block would achieve constant velocity is clarified, emphasizing that the force results in continuous acceleration. Thus, the relationship between force, velocity, and acceleration is crucial in understanding the motion of the block.