Consider a rubber ball freely falling from a height $h=4.9\text{m}$ onto a horizontal elastic plate. Assume that the duration of collision is negligible and the collision with the plate is totally elastic. Then the velocity as a function of time and the height as function of time will be:

For a ball dropped from height $h$:Height $y(t)=h-\frac{1}{2}g{t}^2$. This is a downward opening parabola.Velocity $v(t)=-gt$. This is a straight line with negative slope.Upon elastic collision, the velocity instantly changes from $-v$ to $+v$.The ball then rises, following $y(t)=v_{initial}t-\frac{1}{2}g{t}^2$, until it reaches $h$ again.This cycle repeats. The velocity-time graph is a series of parallel lines with negative slope, interrupted by vertical jumps. The height-time graph consists of repeated parabolic segments.