What does $\dot x$ represent?

For the velocity-time graph shown in the figure,what fraction of the total distance covered in all seven seconds is the distance covered by the body in the last two seconds of its motion?

The figure shows a velocity-time graph of a particle moving along a straight line. The correct acceleration-time graph of the particle is shown as:

The velocity-displacement graph of a particle is shown in the figure. The acceleration-displacement graph of the same particle is represented by:

The position of a particle related to time is given by $x = (5t^2 - 4t + 5) \, m$. The magnitude of velocity of the particle at $t = 2 \, s$ will be $........... \, ms^{-1}$.

Which graph corresponds to an object moving with a constant negative acceleration and a positive velocity?