4the aviation department at the old coleman avenue facility had a small supersonic wind tunnel with a test section 1 inch in height. the operating conditions were such that the reservoir pressure and temperature were 1,2000r and 8 atmospheres. the exit temperature of the tunnel was 9500r. the mass flow rate through the tunnel was 0.5 slug/s. using the energy equation and isentropic relations, determine the reservoir density, exit velocity, exit density, exit pressure and exit area. for air, cp = 6,000 ft lb/slug 0r. assume standard sea level conditions.

In an old-fashioned amusement park ride, passengers stand inside a 3.0-m-tall, 5.0-m-diameter hollow steel cylinder with their backs against the wall. the cylinder begins to rotate about a vertical axis. then the floor on which the passengers are standing suddenly drops away! if all goes well, the passengers will “stick” to the wall and not slide. clothing has a static coefficient of friction against steel in the range 0.60 to 1.0 and a kinetic coefficient in the range 0.40 to 0.70. part a what is the minimum rotational frequency, in rpm, for which the ride is safe? express your answer using two significant figures. f f = rpm

Ultraviolet radiation is dangerous because it has a high enough energy to damage skin cells. what is the best explanation of the relationship between wavelength and wave energy? a) wave energy is related only to frequency, not wavelength. b) longer wavelengths have lower frequencies but higher energy. c) the shorter the wavelength, the lower the frequency and the higher the energy. d) the shorter the wavelength, the higher the frequency and the higher the energy.

Aphase diagram assumes is kept constant.