Question 34797
the 60 feet per second is a red herring as such: it isn't used in the question by you.


The equation is one for height. Find the time taken to return to the ground. What height is the rocket when it finally returns to the ground? Answer that question and put that into the equation and then solve that equation to find the 2 values of t: one will be t=0, since at the start (t=0), the rocket was on the ground). The other answer, a positive value will be the time taken to return to the ground.


Have a go. :-)


jon.