数学英语物理问题

(1)P,Q,R,S四个人去公园玩跷跷板,已知S体重大于P体重,P与R的体重和大于Q与S的体重,Q与R的体重等于P与S的体重.请判断出这四人体重的大小关系.

∵S>P……①,P+R>Q+S……②,Q+R=P+S……③,

∴②-③,get:P-Q>Q-P

So:P>Q……④

∵③&④,

∴R>S

∵①&②,

∴S>P>Q

∴R>S>P>Q.

(2)Whichunitsareusedtomeasureahorse?

a)metresb)handsc)legsd)litres

a

(3)HisChineseteacheris30yearsoldatl____.

least

(4)Whatwordisthefirstwordonpage10inyourEnglish-Chinesedictionary?

Englishword./Ten.(Theseanswersare[uncertain].)

(5)Icanstandstillandgoatthesametime.WhatamI?

Aclock.

(6)Iamsmall,lightandcanmovequickly.Icanspeak,thoughIhavenomouth.Itravelwithoutfeet,andIcanexpressmymaster'sthiughts.WhatamI?

Sound.

(7)Thelittletravellerhasgreatpower.Hetakesadrinkofwater,andrunsathousandmiles.Beforehegoes,hetakesoffhishat.Whenherests,heputsonhishat.Whatishe?

[uncertain]

(8)Thankyouverymuchforc_____forourteam.

cheering

(9)Herparentsdiedintheaccident,butshes____.

survived

(10)Forpeople,theseyoungmenjointhearmywithoutthinkingabouttheirowns_____andd____.

safety,danger.

(11)thiskindofi____canmakenoise.

insects

(12)Thecatsleaveandthem_____play.

mice

(13)Hisworkistomakeb_____chairs.

broad

(14)Ihaveforestswithnotrees.Ihaveriverswithnowater,andIhavecitieswithnohouses.Ihavemountainswithnorocks.WhatamI?

Amap.

(15)某烧杯装满水后总质量为350克，放入一合金块后，溢出一些水，这时总质量为500克，取出合金后，总质量为300克，求合金的密度？

m合金=500g-300g=200g

V合金=V排=m排/ρ水=(350g-300g)/1.0g·cm[-3]=50cm[3]

ρ合金=m合金/V合金=200g/50cm[3]=4g/cm[3]

（16）气压计在一幢大楼底层的示数是755毫米汞柱，在大楼顶上的示数是751毫米汞柱，这幢大楼有多高？若每层楼高是3米，则这幢大楼有几层？

[Thisansweris[uncertain].]

p1=p汞gh1=13.6×10[3]kg/m3·9.8N/kg·755mm=100626.4Pa

p2=p汞gh2=13.6×10[3]kg/m3·9.8N/kg·751mm=100093.28Pa

h=p/(ρ空气g)=(p1-p2)/(ρ空气g)=533.12Pa/(1.29kg/m3·9.8N/kg)≈42.17m

n=h/3m=42.17m/3m≈14(floors)

（17）潜水艇在海中潜行时排水量为800吨，在海面航行时排水量为650吨，试问潜水艇在海面航行时水上部分的体积有多大？要充进多少体积的海水才能潜入海底？（海水的密度为1030千克/立方米）

[Thisansweris[uncertain].]

V=m/ρ海水=(800t-650t)/(1.03×10[3]kg/m3)≈145.6m[3]