1/4 points v Previous Answers SCALCET8 2.7.014. If a rock is thrown upward on the planet Mars with a velocity of 17 m/s. its height (in meters) after t seconds is given by H = 177 - 1.866 (a) Find the velocity of the rock after two seconds. X m/s (b) Find the velocity of the rock when t-a. m/s (c) When will the rock hit the surface? (Round your answer to one decimal place.) t - 9.139 (d) with what velocity will the rock hit the surface? X m/s