To find the initial velocity (V0), we can use the formula:

V = V0 + at

Where:
V is the final velocity (72 km/h or 20 m/s),
V0 is the initial velocity we want to find,
a is the acceleration (assuming constant acceleration),
t is the time (5 seconds).

Since the acceleration is not given, we will assume that it is 0 (constant velocity). Thus the formula simplifies to:

V = V0

Therefore, the initial velocity (V0) is equal to 72 km/h or 20 m/s.