Final answer:
The initial vertical velocity of a ball thrown horizontally from the top of a building is 0 m/s, since it starts with no initial vertical component and gravity acts on it after it is released, increasing the vertical velocity over time.
Step-by-step explanation:
The initial vertical velocity of a ball thrown horizontally from the top of a building is 0 m/s. This is because the ball is only given an initial horizontal velocity and gravity acts on it after it's released. As the ball falls, its vertical velocity increases due to the force of gravity, which is represented by an acceleration of 9.8 m/s2 downward. For any projectile motion without an initial vertical velocity component, the vertical component of velocity just before it hits the ground can be determined using kinematics equations which incorporate the height of the building and the acceleration due to gravity.
However, the information given suggests there is some confusion because it mentions that the graph of the ball's vertical velocity starts at 4.90 m/s, which contradicts the scenario of a horizontally thrown ball from a building (unless this represents a different scenario). If the ball were actually thrown vertically with an initial speed, as a side note, you could use the equation v = u + at, where v is the final velocity, u is the initial velocity, a is the acceleration, and t is time. Nonetheless, the initial vertical velocity for a horizontally thrown projectile remains zero.