Question:

The following plot describes the position of a particle as a function of time.  Find the velocity and speed of the particle at t=-2.5, -1.0, 0, 1.0 and 1.5 sec.

Answer:
We can find the velocity and speed from the slope of the curve.

time(sec) velocity(m/sec) speed(m/sec)
-2.5 0 0
-1.0 1.0 1.0
0 0 0
1 -2.0 2.0
1.5 -2.0 2.0