Flash AS3 movement

Hi there…

I am making a game in AS3 which doesn’t require arrow keys as the way to move. Instead I am wanting the ball to travel with the shape of the ground. The ground would be hilly in some area’s and steep in others so at the hills it speeds up when going down and hills going up it slows down. So the ball is ridding the ground drawn in flash… What could the code be though as I am unsure…

Thanks so much in advance…