A cannon shell is fired straight up from the ground at an initial speed of 225 m/s. After how much time is the shell at a height of 6.20 x 102 m above the ground and moving downward? (a) 2.96 s (b) 17.3 s (c) 25.4 s (d) 33.6 s (e) 43.0 s

Question

5

Answer 1

620 = -4.9 t^2 + 225 t

0 = -4.9 t^2 + 225 t - 620

solve with quadratic formula
... you want the largest solution (on the way down)