There’s a little bit of ambiguity in this question: does it mean to rise up 5 m and fall back down or just to rise 5 m? I’ll write a solution for both as both solutions are just applications of constant acceleration equations and the former is simply the latter solution multiplied by two.
Time to rise up to 5 m.
Write down what you know:
Use this equation:
Substitute in the values:
Obviously the time cannot be negative so the solution for this problem is
If the question requires the time to rise 5 m and fall back down then double the time ⇒