Whenever something is moving in a constant circular motion (such as this water moving in a circle in the blender), then you can find the centripetal acceleration of the object with this formula:
a = v^2 / r
In this equation, the "v" is the velocity and the "r" is the radius of the circular motion. The formula is to take the velocity squared and divide that by the radius to get acceleration. In this particular problem, the velocity of the water is simply 2 m/s (as given). The radius is 10 cm, however if we convert this to meters then it is 0.1 m (by dividing by 100 we convert from centimeter to meter this way). So, plug in the values into the formula above.
a = (2m/s)^2 / (0.1m)
a = 40 m/s2
The acceleration is therefore 40 meters per second squared.