Three dogs pull a sled that has a mass of 215 kg. If the coefficient of kinetic friction between the sled and the snow is 0.11, what force would the dogs need to pull to keep the sled moving at a constant velocity? (Hint: Consider what the net force would need to be if moving at a constant velocity)

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?