What is it called if there are no particles present?

What is the stall speed at sea level of an airplane that weights 10000 lbs., has a wing area of 300ft^2, and a maximum lift coefficient of 1.4? what is the stall speed if flaps that double cl,max are applied?

The frequency of the fundamental of the guitar string is 320 hz. at what speed v do waves move along that string?

The process of predicting values that extend beyond the range of data points is called absolute value extrapolation interpolation prediction for any given: )