有没有物理好英语又好的达人帮我看看这些题目?
1.Ifthecoefficientofkineticfrictionbetweena28kgcrateandtheflooris0.25,whathorizontalforce(inN)isrequiredtomovethecrateataconstantspeedacrossthefloor?
2.Apersonhasareasonablechanceofsurvivinganautomobilecrashifthedecelerationisnomorethan30"g's"(recallthatg=9.8m/s2).Calculatetheforce,inN,ona72kgpersonacceleratingatthisrate.
3.Anelevatoristravellingupwardsataconstantaccelerationof4.7m/s2.Ifa68kgpersonintheelevatorisstandingonabathroomscale,whatwouldtheymeasureastheirapparentweight(inN)?
4.Supposeacircularplatformisrotatingataconstantrateof17rev/min.Howfarawayfromthecentrewouldoneneedtostandinordertohaveanradialaccelerationof6.3m/s2?Expressyouranswerincm.
5.SupposetheCanadianSpaceAgencywishedtoplacea773kgsatelliteinacircularorbitaroundthemoonsuchthatthesatellitetakes17.4hoursforonecompleterevolutionaroundthemoon.Howfarawayfromthesurfaceofthemoon(inkm)wouldthesatellitebelocated?N.B.MassofMoon=7.35x1022kg,RadiusofMoon=1.74x103km.
顺便帮我看看这题好吗?
Howisthequantitycalled'impulse'calculated?
a.fromthechangeinmomentum?
b.fromthechangeinacceleration?
c.thechangeinthekineticenergy?
答案只需要准确数字,不需要单位,补充问题说一下选哪个就好