What happens to the density of a gas when it is compressed? - the density does not change -the density increases -the density decreases

Need only answer if you think you know it

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?

Using the free-body diagram, calculate the net force acting on the sled. is the sled in a state of dynamic equilibrium?