graphs Questions

A student measures the focal length of a convex lens by measuring object distance ‘$u$ ’ and image distance ‘$v$ ’. The graph between $u$ and $v$ should look like:

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: