Citation:
Vertical position refers to the height or displacement above/below a reference point along an up/down axis. In the given context, the vertical position of the ball is represented by y(t) = -9.81t^2.
Displacement measures the change in an object's position from its starting point to its ending point.
Gravity is a force that pulls objects towards each other. In this context, gravity affects the vertical motion of the ball.
Free Fall: Free fall refers to an object falling under only the influence of gravity without any air resistance or other forces acting upon it.