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University Physics Volume 1

# Key Equations

### Key Equations

 Density of a sample at constant density $ρ=mVρ=mV$ Pressure $p=FAp=FA$ Pressure at a depth h in a fluid of constant density $p=p0+ρghp=p0+ρgh$ Change of pressure with height in aconstant-density fluid $dpdy=−ρgdpdy=−ρg$ Absolute pressure $pabs=pg+patmpabs=pg+patm$ Pascal’s principle $F1A1=F2A2F1A1=F2A2$ Volume flow rate $Q=dVdtQ=dVdt$ Continuity equation (constant density) $A1v1=A2v2A1v1=A2v2$ Continuity equation (general form) $ρ1A1v1=ρ2A2v2ρ1A1v1=ρ2A2v2$ Bernoulli’s equation $p+12ρv2+ρgy=constantp+12ρv2+ρgy=constant$ Viscosity $η=FLvAη=FLvA$ Poiseuille’s law for resistance $R=8ηlπr4R=8ηlπr4$ Poiseuille’s law $Q=(p2−p1)πr48ηlQ=(p2−p1)πr48ηl$
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