Hi there, I am in college algebra. I haven't done any of this in 3 years and am a bit rusty, I am very far behind and don't understand how to do this! Can someone please not just give me answers but help explain how to do a problem for me? The problem is this... An object is propelled vertically upward with an initial velocity of 20 meters per second. The distance s(in meters) of the object from the ground after t seconds is s=4.9t^2+20t a) When will the object be 15 meters above the ground? b) when will it strike the ground? c) Will the object reach a height of 100 meters. I am guessing that with the a) you would make s=15 but as for what to do from there I have no idea. Same for be except making s=0?? And as far as c I don't have a clue. How could you answer c without knowing the rate that the object slows down to know if it would ever make it that high? I just don't get it!