According to your question,
acceleration due to gravity on earth, a = 9.8m/s
initial velocity, u = 0
final velocity, v = 30m/s
As we know that, v = u + at
So,
[tex]t = \frac{(v - u)}{a} [/tex]
[tex] = \frac{(30 - 0)}{9.8} [/tex]
[tex] = \frac{30}{9.8} [/tex]
[tex]3.06122...[/tex]
keep smiling ❣️
