Question

an arrow is shot vertically upward 2 seconds later it is at an height of 42m (not necessarily the highest point) with what velocity was the arrow shot how long was the arrow in flight altogether

Answer 1

average velocity = distance / time =
42 m / 2 s = 21 m/s

average velocity =
(initial + current) / 2

gravity slowed the arrow for 2 sec
... current = initial - (2 * 9.8)

(Vi + Vi - 19.6) / 2 = 21 m/s

solve for Vi

time up = time down

flight time = 2 (Vi / g)