Final answer:
The speed of sound through an aluminum bar is generally between 4000 to 6000 m/s, much faster than in air, and is not provided in the question. Sound in aluminum travels faster due to its density and elasticity, and sound's speed in air is mostly independent of frequency in the audible range.
Step-by-step explanation:
When a bar of aluminum is hit with a hammer, the speed of sound that travels through the aluminum depends on various properties of aluminum, such as its density and elastic properties. However, it is important to note that the speed of sound in solids like aluminum is typically much higher than in air.
The exact speed of sound in aluminum is not provided in the question, but for most metals, it ranges from 4000 to 6000 m/s, substantially faster than the speed of sound in air, which is approximately 343 m/s at 20°C (or 338 m/s at 0°C as given in one of the reference questions). The speed of sound in air is largely independent of frequency for the audible range, which is crucial for musical performances to sound coherent at different distances from the source.