It is desired to produce and aligned carbon fiber-epoxy matrix composite having a longitudinal tensile strength of 640 mpa. calculate (a) the critical fiber length in mm, and (b) the volume fraction of fibers necessary if

(1) the average fiber diameter is 0.029 mm,

(2) the average fiber length is 2.2 mm,

(3) the fiber fracture strength is 5200 mpa,

(4) the fiber-matrix bond strength is 18 mpa,

(5) the matrix stress at fiber failure is 16.1 mpa.

The mass flow rate of the fluid remains constant in all steady flow process. a)- true b)- false

Aloaded platform of total mass 500 kg is supported by a dashpot and by a set of springs of effective stiffness 72 kn/m. it is observed that when the platform is depressed through a distance x = 12.5 cm below its equilibrium position and then released without any initial velocity; it reaches its equilibrium position in the shortest possible time without overshoot. find the position and velocity of the loaded platform 0.10 sec. after its release. if a further load of 400 kg is added to the platform, find, i) the frequency of damped vibrations, and i) the amplitude of vibration after 2 complete oscillations, given that the initial amplitude is 15 cm.

An air conditioning system consist of a 5 cm diameter pipe, operating at a pressure of 200 kpa. the air initially enters the pipe at 15°c with a velocity of 20 m/s and relative humidity of 80%. if the heat supply throughout the process is 960 w, determine the relative humidity and the temperature at the outlet