A small stone is kicked from the edge of a cliff. Its x- and y-coordinates as functions of time are given by x = 19.2t and y = 4.12t − 4.90t^2,where x and y are in meters and t is in seconds. (Do not include units in your answer.) Write a vector expression for the stone's position as a function of time (in m), using the unit vectors î and ĵ. (Give the answer in terms of t.)