To calculate the velocity (V), we can use the formula:

V = S / t

Plugging in the given values:

V = 10 km / 30 sec

Convert kilometers to meters (1 km = 1000 m):

V = 10,000 m / 30 sec

Divide to find the velocity:

V = 333.33 m/s

Therefore, the velocity is 333.33 meters per second.