Given in the table below are the fundamental units of measure for the Systeme Internationale - or the MKS metric system. Also shown is a second popular collection of units is called the CGS system.
SI fundamental unitsQuantity NameMKS UnitCGS Unitlength metermcm mass kilogramkggtime secondsselectric current ampereAtemperature kelvinKamount of substance molemolluminous intensity candelacd These are the basic units from which all other metric units of measure are derived. For example: Speed is a derived quantity that expresses how rapidly an object travels a given distance with respect to time. It is measured in m/sec. (scalar) quantity: speed(formula) variable: runits of measure: m/sec Presented below are the most common derived units from mechanics. This link will take you to a more complete summary of the formulas and units of measure used in standard introductory physics courses. namevector/scalarvariablecommon formulaunit of measurerelationshipslengthscalarL m1 m = 100 cmheightscalarh m areascalarAA = L•wm21 m2 = (100 cm)2volumescalarVV = L•w•hm31 m3 = (100 cm)3massscalarm or M kg1 kg = 1000 gdensityscalarDD = M / Vkg/m31 kg/m3 = 10-3 g/cm3distancescalard m displacementvectors m timescalart sec speedscalarrr = d / tm/sec velocityvectorvv = s / tm/sec momentumvectorpp = mvkg m/sec accelerationvectoraa = Δv /Δtm/sec/secm/sec2gravityvectorgg = GME/RE2m/sec29.8 m/sec2forcevectorFF = ma MKS: kg(m/sec2) nt, N (newton)CGS: g(cm/sec2) dyne1 N = 105 dynestensionvectorT ntstrings, wiresspring constantscalarkF = ksnt/m impulsevectorJJ = Δp = Ftkg m/secnt secpressurevectorPP = F / Ant/m2Pa (Pascal)workscalarWW = Fs
nt m = J (Joule)
erg1 J = 107 ergsenergyscalarEW = ΔEkg(m2/sec2)nt m = J (Joule)gravitational potential energyPEg = mgh elastic potential energyPEe = ½ks2 kinetic energyKE = ½mv2 powerscalarPP = W / t watt = J / secfrequencyscalarff = #events / t1/sechz (hertz)periodscalarTT = 1 / fsec anglescalarθ ° or radians90° = π/2 radstorquevectorττ = FL⊥m nt temperaturescalarT K or °C0 K = -273°C
Speed is a derived quantity that expresses how rapidly an object travels a given distance with respect to time. It is measured in m/sec. (scalar) quantity: speed(formula) variable: runits of measure: m/sec
(scalar) quantity: speed(formula) variable: runits of measure: m/sec