As shown in Video V1.9, surface tension forcescan be strong enough to allow a double-edge steel razor bladeto float on water, but a single-edge blade will sink. Assumethat the surface tension forces act at an angle relative to thewater surface as shown in Fig. P1.124. (a) The mass of thedouble-edge blade is 0.64 103 kg, and the total length of itssides is 206 mm. Determine the value of required to maintainequilibrium between the blade weight and the resultantsurface tension force. (b) The mass of the single-edge bladeis 2.61 103 kg, and the total length of its sides is 154 mm.Explain why this blade sinks. Support your answer with thenecessary calculations.
Lecture 8 Identification of Birth Cohorts: Aging of a cohort refers to all of its members becoming older If you know expected death rate, you can calculate percentage of its members who will die b/w birth and a certain age Different cohorts: greatest generation, silent generation, baby boomers('46-'64), generation x, generation y/millennial('81, '97), generation z Baby Boomers: Why ^ Fertility Rate o Higher marriage rate o Spike in 1st births + multiple kids o Married people stopped postponing child bearing o Wealthy successful people who could afford kids o Less workplace competition/ ^ wages Baby Bust o More job competition o Birth control + legalized abortions o Less wealthy, tighter job market o Delayed marriage, working women Household Formation Important driver of housing demand (sing/multifam properties) Household formation needed to sustain housing demand, but lack of homes can weigh on formation of households Older adults drive household formation Lower Household Formation Rates of young: o Living w/ parents b/c of high unemployment rates and delayed marriage o Delayed childbearing o Student loan debt o *men are more likely to be living w/ parents than women Immigrants have higher fertility rates and household formation rates o Slower pop growth from slowed immigration