Find the acceleration of the specified object. (Hint: Recall that if a variable is changing at a constant rate, its acceleration is zero.) A boat is pulled into a dock by means of a winch 15 feet above the deck of the boat (see figure). The winch pulls in rope at a rate of 7 feet per second. Find the acceleration (in ft/sec?) of the boat when there is a total of 17 feet of rope out. (Round your answer to three decimal places.) ft/sec? y fr