Aboy finds an abandoned mine shaft in the woods, and wants to know how deep the hole is. he drops in a stone, and counts 4 seconds before he hears the "plunk" of the stone hitting the bottom of the shaft. approximately how deep is the shaft? (assume a gravitational acceleration of 9.8 m/s2 and no significant air resistance.)

An important dimensionless parameter concerned with very high-speed flow is the mach number, defined as v/c, where v is the speed of the object such as an airplane or projectile, and c is the speed of sound in the fluid surrounding the object. for a projectile traveling at 1170 mph through air at 50 ˚f and standard atmospheric pressure, what is the value of the mach number?