The speed of sound doesn't change based on the year. It's a physical constant determined by the properties of the medium through which sound travels.

Here's why:

* Speed of sound in air: The speed of sound in air depends primarily on temperature and, to a lesser extent, on humidity.

* Constant for a given medium: For a specific medium at a specific temperature and pressure, the speed of sound is always the same.

Therefore, the speed of sound in 1947 was the same as it is today.

To calculate the speed of sound in air, you can use the following formula:

* Speed of sound (m/s) = 331.5 + 0.6 * Temperature (°C)

For example:

* At 20°C, the speed of sound in air is approximately 343.5 m/s.

So, whether it was 1947 or 2023, the speed of sound in air at 20°C would still be around 343.5 m/s.