PracticeQuestionsofWork,Energy,andPower1.Howmuchworkdoesapersondoinpushingaboxwithaforceof10Noveradistanceof4.0minthedirectionoftheforce?(A)0.4J(B)4.0J(C)40J(D)400J(E)4000J2.Apersonpushesa10kgboxataconstantvelocityoveradistanceof4m.Thecoefficientofkineticfrictionbetweentheboxandtheflooris0.3.Howmuchworkdoesthepersondoinpushingthebox?(A)12J(B)40J(C)75J(D)120J(E)400J3.Howmuchworkdoestheforceofgravitydoinpullinga10kgboxdowna30ºinclinedplaneoflength8.0m?Notethatsin30=cos60=0.500andcos30=sin60=0.866.(A)40J(B)69J(C)400J(D)690J(E)800J4.Howmuchworkdoesapersondoinpushingaboxwithaforceof20Noveradistanceof8.0minthedirectionoftheforce?(A)1.6J(B)16J(C)160J(D)1600J(E)16000J5.Thefigurebelowisaforcevs.displacementgraph,showingtheamountofforceappliedtoanobjectbythreedifferentpeople.Alappliesforcetotheobjectforthefirst4mofitsdisplacement,Bettyappliesforcefromthe4mpointtothe6mpoint,andChuckappliesforcefromthe6mpointtothe8mpoint.Whichofthethreedoesthemostworkontheobject?(A)Al(B)Betty(C)Chuck(D)AlandChuckdothesameamountofwork(E)BettyandChuckdothesameamountofwork6.Whenacar’sspeeddoubles,whathappenstoitskineticenergy?(A)Itisquartered(B)Itishalved(C)Itisunchanged(D)Itisdoubled(E)Itisquadrupled7.Aworkerdoes500Jofworkona10kgbox.Iftheboxtransfers375Jofheattothefloorthroughthefrictionbetweentheboxandthefloor,whatisthevelocityoftheboxaftertheworkhasbeendoneonit?(A)5m/s(B)10m/s(C)12.5m/s(D)50m/s(E)100m/s8.Apersononthestreetwantstothrowan8kgbookuptoapersonleaningoutofawindow5mabovestreetlevel.Withwhatvelocitymustthepersonthrowthebooksothatitreachesthepersoninthewindow?(A)5m/s(B)8m/s(C)10m/s(D)40m/s(E)50m/sQuestions9and10refertoaforkliftliftingacrateofmass100kgataconstantvelocitytoaheightof8moveratimeof4s.Theforkliftthenholdsthecrateinplacefor20s.9.Howmuchpowerdoestheforkliftexertinliftingthecrate?(A)0W(B)2.0103W(C)3.2103W(D)2.0104W(E)3.2104W10.Howmuchpowerdoestheforkliftexertinholdingthecrateinplace?(A)0W(B)400W(C)1.6103W