Problem 15E
Gas Characteristics; Pressure (Sections)
Suppose that a woman weighing 130 lb and wearing highheeled shoes momentarily places all her weight on the heel of one foot. If the area of the heel is 0.50 in.2, calculate the pressure exerted on the underlying surface in (a) kilopascals, (b) atmospheres, and (c) pounds per square inch.
Day 1 1/4/2016 Mondays 56:30 Sections with the Professor Adriane Steinacker First Homework posted this Friday Lectures are Webcast Login: phys5b Password: Y0ung2sl1t Class Materials: rulers, compass, scientific calculator Yellow is her favorite color 1) Density (mass density) lett rho ρ ρ = mass over volume [ρ] = kg v m3 1 L (Liter) = 100cm 1m3 = 1000L 1 g kg converting 1 cm3= m 3 Assume air is made of Nitrogen molecules N atomic mass z = 7 7 protons and 7 electrons 2 A = 14 so 7p & 7e Mass of proton = 1.67 x 10 27 Mass of neutron = M p MN2 x 14 x 1.67 x 10 = 4.676 x 10 26 mas of one Nitrogen molecule 1.28 kg air 25 N2= 4.676 x 1 kg = 2.7 x 10 in one meter cube of air 2) Pressure ← water bottle pressure depends on depth a) why does the water flow out dP 1 dP F = dx F ~ ρ dx pressure force in a fluid FN b) How do we define pressure P = A normal force over the area Units of Pressure [P] = mN2 = 1 Pa Pascal 5 or 1 standard atmosphere 1atm = 1.013 x 10 Pa
