Integratingnumerically, we get
So the probabilityof selectingat randoma personwith an IQ scoreabove is That’s aboutone
personin every individuals!
ReviewQuestions
- A particlemovesalongthe -axisby a force
If the particlehas alreadymoveda distanceof metersfromthe origin,whatis the workdoneby the
force?
- A forceof acts on an objectwhenit is metersawayfromthe origin.Howmuchworkis
doneby this forcein movingthe objectfrom to meters? - In physics,if the forceon an objectvarieswith distancethen workdoneby the forceis definedas (see
Example5.15)
That is, the workdonecorrespondsto computingthe area underthe forcegraph.For example,the strength
of the gravitationalfield varieswith the distance from the Earth’s center. If a satelliteof mass is to be
launchedinto space,then the forceexperiencedby the satelliteduringand after launchis
where is the massof the Earthand is the UniversalGravita-
tionalConstant.If the massof the satelliteis and we wish to lift it to an altitudeof
abovethe Earth’s surface,how muchworkis neededto lift it? (Radiusof Earthis )
4.Hook’s Lawstatesthat whena springis stretched unitsbeyondits naturallengthit pullsbackwith a
force
where is calledthespringconstantor thestiffnessconstant.To calculatethe workrequiredto stretchthe
springa length we use