{4) {a} [8 pts] A 5 n1 ladder is leaning against a house when its base starts to slide away. By the time the base is 3 n1 from the house, the base is moving at the rate of 1.6 mfsec. At what rate is the area of the triangle formed by the ladder, wall, and ground changing then? [b] [8 pts] Two carts, A and B , are connected by a rope 35 ft long that passes over a pulley P (see the gure below.) The point Q is on the oor 12 ft directly beneath P and between the carts. Cart A is being pulled awaji,F from Q at a speed of 4 ft fs. How fast is cart B moving toward Q at the instant when cart A is 9 ft from Q? P 1211