6. If a rock is thrown upward on the planet Mars with a velocity of 10 mfg, its height in meters r seconds later is given by y = lOt 1.86:2. (a) Find the average velocity over the given time intervals: (i) [1, 2] (ii) [1, 1.5] (iii) [1, 1.1] (iv) [1, 1-01] (v) [1, 1.001] (b) Estimate the instantaneous velocity when r = l