The mole fraction of oxygen in dry air near sea level is 0.20948. the concentration of
oxygen is molecules per liter, assuming an atmospheric pressure of 739 torr and
a temperature of 29.5°c
a) 6.23
b) 0.00819
c) 4.93 × 1021
d) 3.75 × 1024
e) 5.07 × 1022

In a wind tunnel the speed changes as the cross sectional area of the tunnel changes. if the speed in a 6' x 6' square test section is 100 mph, what was the speed upstream of the test section where the tunnel measured 20' x 20'? use conservation of mass and assume incompressible flow. conservation of mass requires that as the flow moves through a path or a duct the product of the density, velocity and cross sectional area must remain constant; i. e., that ova-constant. a model is being tested in a wind tunnel at a speed of 100 mph if the flow in the test section is at sea level standard conditions, what is the pressure at the model's stagnation point? (a) the tunnel speed is being measured by a pitot-static tube connected to a u- tube manometer. what is the reading on that manometer in inches of water? (b) at one point on the model a pressure of 2058 psf is measured. what is the local airspeed at that point?

Ablock of steel has a density of 0.29lbs per cubic inch. if the block has dimensions of 1 inch by 1 inch by 3 inches, what is its weight? a. 0.29lbs b. 0.58lbs c. 0.87lbs d. 1lbs

Calculate the capacitance of a system that stores 2.0 x 10^-10c of charge at 100.0 v. use c=q/v. a. 2.0 x 10^-12 f b. 2.0 x 10^-8 f c. 5.0 x 10^11 f d. 5.0 x 10^7 f