Find initial velocity

Question

A ball was thrown vertically downwards with initial velocity v0. After 2 s of free fall it got 11 times greater velocity than its initial velocity. standard acceleration of free fall is 10 m/s^2. What was the initial velocity?

Answer 1

Use v = v0 + at, with a = g = 10 m/s^2 and t = 2 s. Let v = 11 v0.

v = v0 + at

11 v0 = v0 + (10)(2)

11 v0 = v0 + 20

10 v0 = 20

v0 = 2 m/s