A graph of position versus time for a certain particle moving along the x-axis is shown in the figure below. The vertical divisions of the graph represent 6.0 m and the horizontal divisions represent 3.0 s. Find the instantaneous velocity at the following instants: x(m) ((s) (a) t = 3.00 s m/s (b) t = 9.00 s m/s (c) t = 13.50 s m/s (d) t = 22.50 s m/s