If you were to throw a large log over the edge of the Grand Canyon and it took 5.75 seconds to hit the ground calculate the velocity of the log at impact in m/s?

Scientists follow specific processes in order to determine valid explanations and conclusions from observations. david observed strange lights in the sky above his home outside of roswell, new mexico. the only explanation that makes sense to him is that there are ufos in the area. what should david do next to verify his explanation?