A car moves towards a hill with speed vc. It blows a horn of frequency f which is heard by an observer following the car with speed v₀. The speed of sound in air is v. Image
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Question

A car moves towards a hill with speed vc. It blows a horn of frequency f which is heard by an observer following the car with speed v₀. The speed of sound in air is v. Image

G1 Physics · Accepted Answer

Step 1: Use v = √(B/ρ) in a fluid, v = √(Y/ρ) for longitudinal waves in a solid, or v = √(γRT/M) for an ideal gas. Step 2: Form any required ratio before substituting values. Step 3: Evaluate with the data given. Final: B: Wavelength reaching the hill = (v − vc)/f; D: Beat frequency = [2vc(v + v₀)/(v² − vc²)]f.