4. Let b be a positive number A 2b m ladder is leaning against the wall of a church, a cat is attached to the bottom of the ladder. He sees a mouse (or a field mouse...I can't tell them apart) and goes towards it, at a constant speed of 2 m/sec. In doing so, it takes the scale with it. How fast does the top of the ladder slide down the wall when the bottom of the ladder is 8m above the ground? b ? m/sec bxo avec 2b 2 m/sec