QUESTION 7 (Start on a new page.) A sound wave is produced by a source placed a certain distance from a building as shown below. The echo reaches the source after 8 seconds. The speed of sound in air s \( 340 \mathrm{~m} \cdot \mathrm{~s}^{-1} \).

To find the distance to the building, we can use the formula that relates speed, distance, and time, \( \text{Distance} = \text{Speed} \times \text{Time} \). Since the sound wave travels to the building and back, the time taken (8 seconds) is for the round trip. First, we calculate the distance traveled by the sound: \( \text{Distance} = 340 \, \text{m/s} \times 8 \, \text{s} = 2720 \, \text{m} \). Since this is the distance to the building and back, we divide by 2, giving us a distance to the building of \( 1360 \, \text{m} \). Interesting fact: The speed of sound varies with temperature and medium. In warmer air, sound travels faster because the molecules are more energetic and can transmit vibrations more quickly. So, if you ever find yourself at a concert in the summer, that music might just reach you a bit quicker! In real-world application, understanding sound waves and their properties is crucial in various fields such as architecture, where sound design plays an essential role in creating spaces with optimal acoustics. For example, concert halls are built with specific shapes and materials to ensure that sound waves reflect and dissipate in a way that produces a pleasing experience for the audience.