Bob walks to Jack's house. He walks 900 meters East then realizes that he walked too far. He turns around and walks 300 meters West. The entire walk takes him 15 seconds. What was his speed per second?

What is the mass of the same rock on the earth

How does an observation about an object differ from an inference about that object

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?