Question: User: Scene 4: Solved Numerical Example 1 - The Train Horn Visual Prompt for AI Video Generator: Prompt: 3D animation near a railway crossing[cite: 14]. A train moving at Vs = 20 m/s approaches a stationary bystander (Vo = 0 m/s) while sounding a 720 Hz horn[cite: 14]. Speed of sound v = 340 m/s[cite: 14]. Mathematical graphic overlay step 1: Approaching f' = (340 / (340 - 20)) * 720 = 765 Hz[cite: 14]. The train passes the crossing and departs[cite: 14]. Graphic overlay step 2: Departing f' = (340 / (340 + 20)) * 720 = 680 Hz[cite: 14]. Numbers light up in neon orange. English Voiceover & Text: Voiceover: "Let's solve Example 1! For a train approaching at 20 m/s with a 720 Hz horn, the observed frequency rises to 765 Hz[cite: 14]. Once the train passes and recedes, the frequency drops to 680 Hz[cite: 14]!"