To calculate the average speed, we need to divide the total distance traveled by the total time taken.

Given:

Distance traveled (d) = 50 cm

Time taken (t) = 2 s

Average speed (v) = d/t

Substituting the values, we get:

v = 50 cm / 2 s

Now, we can convert centimeters (cm) to meters (m) to get the speed in SI units:

1 cm = 0.01 m

Therefore, 50 cm = 50 * 0.01 m = 0.5 m

Substituting the converted value, we get:

v = 0.5 m / 2 s

Calculating the average speed, we find:

v = 0.25 m/s

Hence, the average speed of the ball is 0.25 m/s.