Child drops a ball from a window. The ball strikes the ground in 3.0 seconds. What is the velocity of the ball the instant before it hits the ground?

The velocity of the ball just before it hits the ground is approximately 29.4 m/s downwards. This can be calculated using the formula v = gt, where g is the acceleration due to gravity (9.8 m/s^2) and t is the time of flight (3.0 s).