ANSWER -
If a waterfall and a dam have the same height, the waterfall would have more kinetic energy. This is because kinetic energy depends on both height (potential energy) and velocity. A waterfall, being a free-falling stream of water, has a greater velocity than a dam, where the water is held back by a barrier. The greater velocity of the waterfall means that it has a greater kinetic energy.
Kinetic energy (KE) = 0.5 * mass * velocity^2, where mass is the mass of the water and velocity is its speed. As velocity increases, so does kinetic energy.