A web page designer creates an animation in which a dot on a computer screen has a position of r "" [4.0 cm +(2.5 cm/s2),z]i + (5.0 cm/s)IJ. (a) Find the magnitude ami direction of the dot's average velocity between I = 0 and I = 2.0 s. (b) Find the magnitude and direction of the instantaneous velocity at I = 0, I = 1.0 S, and I = 2.0 s. (c) Sketch the dot's trajectory from I = 0 to I = 2.0 s, and show the velocities calculated in pan (b).