Two carts, a and b, are connected by a rope 39 ft long that passes over a pulley p. Two carts on a horizontal surface are connected by a rope that passes over a pulley. The distance between the pulley p and the point q on the horizontal surface is 12 ft. Cart a is to the left of point q, and cart b is to the right of point q. Both carts are traveling from right to left. The point q is on the floor 12 ft directly beneath p and between the carts. Cart a is being pulled away from q at a speed of 4 ft/s. How fast (in ft/s) is cart b moving toward q at the instant when cart a is 5 ft from q? (round your answer to two decimal places. ).