Answer:
39.2 m/s
Explanation:
We use the formula for velocity under the acceleration due to gravity, and understanding the the dropped brick was not imparted initial velocity.
vf = vi + g * t
using g = 9.8 m/s^2 and t= 4 seconds, we get
vf = 0 + 9.8 * 4 = 39.2 m/s
