Aweb page designer creates an animation in which a dot on a computer screen has position
r⃗ =[4.0cm+(2.5cm/s2)t2]ı^+(5.0cm/s)tȷ ^
. (a) find the magnitude and direction of the dot’s average velocity between t = 0 and t = 2.0 s.(b) find the magnitude and direction of the instantaneous velocity at t = 0, t = 1.0 s, and t = 2.0 s. (c) sketch the dot’s trajectory from t = 0 to t = 2.0 s, and show the velocities calculated in part (b).