Final answer:
The kinetic energy of the river water is approximately 1,521,604 J.
Step-by-step explanation:
The kinetic energy of an object is given by the formula KE = 0.5 * mass * velocity^2. In this case, the mass of the river water is 100 tonnes, which is equal to 100,000 kg. The velocity of the water is 12.5 km/hr, which is equal to 3.4722 m/s.
Plugging these values into the formula, we get KE = 0.5 * 100,000 * (3.4722)^2 = 1,521,604.17 J. Therefore, the kinetic energy of the river water is approximately 1,521,604 J.