4. (6 points) A rock is dropped from way up high in the air. Its velocity in meters per second is given by the function v(t) = -9.8t, where t is the number of seconds after it was dropped. Use a definite integral (and the Fundamental Theorem of Calculus) to find the displacement of the rock between t = 1 and t = 3 seconds. (Make sure to include correct units.)