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.

Amass of m 1.5 kg of steam is contained in a closed rigid container. initially the pressure and temperature of the steam are: p 1.5 mpa and t 240°c (superheated state), respectively. then the temperature drops to t2= 100°c as the result of heat transfer to the surroundings. determine: a) quality of the steam at the end of the process, b) heat transfer with the surroundings. for: p1.5 mpa and t 240°c: enthalpy of superheated vapour is 2900 kj/kg, specific volume of superheated vapour is 0. 1483 m/kg, while for t 100°c: enthalpy of saturated liquid water is 419kj/kg, specific volume of saturated liquid water is 0.001043m/kg, enthalpy of saturated vapour is 2676 kj/kg, specific volume of saturated vapour is 1.672 m/kg and pressure is 0.1 mpa.

Prove the equivalence between the two statements of the 2nd law of thermodynamics (i.e., a violation of one statement leads to the violatio the other statement)

With increases in magnification, which of the following occur? a. the field of view decreases. b. the ambient illumination decreases. c. the larger parts can be measured. d. the eyepiece must be raised.