When a skydiver jumps out of a hovering helicopter, the initial forward velocity is indeed zero. As soon as the skydiver leaves the helicopter, they experience the force of gravity pulling them downward. This force causes the skydiver to accelerate in the downward direction.

The acceleration of the skydiver due to gravity is approximately 9.8 meters per second squared (9.8 m/s²). This means that every second, the skydiver's velocity increases by 9.8 m/s in the downward direction.

It's important to note that air resistance also acts on the skydiver. As the skydiver falls, air resistance increases due to the increasing speed of the skydiver. This force opposes the force of gravity and eventually causes the skydiver to reach a constant velocity known as terminal velocity. Terminal velocity is the point at which the force of gravity is balanced by the force of air resistance.

The acceleration of the skydiver is the same as that of any object in free fall in the Earth's gravitational field, regardless of the initial forward velocity.