7. [-/4 Points] DETAILS SCALC9 2.1.012.MI. MY NOTES If a rock is thrown upward on the planet Mars with a velocity of 19 m/s, its height above the ground (in meters) after t seconds is given by H = 19t - 1.86t- (a) Find the velocity (in m/s) of the rock after 2 seconds. m/s (b) Find the velocity (in m/s) of the rock when t = a. m/s (c) When (in seconds) will the rock hit the surface? (Round your answer to one decimal place.) t = S (d) With what velocity (in m/s) will the rock hit the surface? m/s Need Help? Read It Master It MY NOTES DETAILS SCALC9 2.1.523.XP.MI.SA