A car that is about to enter a tunnel and is moving at a top speed of 50.0 [kph]. To signal that the car is coming, the car driver blows a horn, producing a sound of some frequency. At that time, the temperature of the air is about 20.0°C. What is the speed of sound in air at this temperature? If the sound is reflected back by a wall at the opening of the tunnel, what is the ratio of the incident frequency and the received frequency heard by the car driver?

A car that is about to enter a tunnel and is moving at a top speed of 50.0 [kph]. To signal that the car is coming, the car driver blows a horn, producing a sound of some frequency. At that time, the temperature of the air is about 20.0°C. What is the speed of sound in air at this temperature? If the sound is reflected back by a wall at the opening of the tunnel, what is the ratio of the incident frequency and the received frequency heard by the car driver?