The quasar that appears the brightest in our sky, 3c 273, is located at a distance of 2.4 billion light-years. the sun would have to be viewed from a distance of 1300 light-years to have the same apparent magnitude as 3c 273. using the inverse square law for light, estimate the luminosity of 3c 273 in solar units.

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?