Question

A ball is rolling across the floor. How could you apply an unbalanced force to change the speed or direction of the ball.

Answer 1

I think wind might apply an unbalanced force to change speed or direction of the ball.

Answer 2

You could roll a bowling ball to divert the direction of the ball since it is a greater mass than the other ball that is rolling on the floor. It is because of Newtons "first law of motion" or the "laws of inertia" Hope this helps and enjoy the rest of your day :D