Answer:
The speed of sound in diamond is about **12,000 metres per second (39,000 ft/s)** which is about **35 times** its speed in air³. To convert this to feet per hour (ft/hr), we can use the following conversion factors:
1 meter = 3.28084 feet
1 second = 3600 hours
Therefore, the speed of sound in diamond in feet per hour (ft/hr) is:
12,000 m/s x 3.28084 ft/m x 3600 s/hr = 141,732,480 ft/hr