Why should a coworker sigh off as a witness for an engineering notebook?

a. to double check the work.
b. many engineers skip this essential step.
c. because fraud is common in engineering
d. this step is needed only for inexperienced engineers.

2. a closed system

a. requires permission to access.
b. is particularly difficult to study.
c. prevents elements from leaving.
d. does not contain natural elements.

Asteam is contained in a rigid tank with a volume of 1 m3. initially, the pressure and temperature are 7 bar and 500 oc, respectively. the temperature drops due to cooling process. determine: (1) the temperature at which condensation begins in °c, (2) the fraction of the total mass that has condensed when the pressure decreased to 0.5 bar. (3) the volume in m3 occupied by saturated liquid at the final state?