How long will it take for a sound impulse to travel through a copper rod 25 kilometers long?

By conducting exhaustive, high-intensity online research for about 15 seconds, I found a source that says the speed of sound in copper is 4600 m/s. (You could easily have completed the same research project in about 1/3 of the time it took you to type and post the question here.)

Time it takes = (distance) / (speed)

Time = (25,000 meters) / (4600 m/s)

Time = (25 / 4.6) km-sec/km

Time = 5.43 seconds