题目
近与 近与 近与质量为M的物体在光滑的水平面上做简谐振动.振幅是12cm,在距平衡位置6cm处速度为24cm/s近与(1)振动周期 (2)当速度为12cm/s时的位移近与好几年没碰物理 一下子想不起来了近与A.2008--the Potato#39;s New MissionB.In Praise of the PotatoC.The History of the PotatoD.The Potato and Globalization2.[单选题]Europeans began to eatpotatoes in the 18th century becauseE.there was a serious food shortageF.they realized that potatoes tasted goodG.food safety had been greatly improvedH.eating potatoes had become fashionable3.[单选题]Paragraph 3 mainly describesI.why the potato became popular in the north of EnglandJ.why the potato was important in England#39;s population growthK.how the potato contributed to England#39;s industrial developmentL.how the potato helped improve England#39;s working conditions4.[单选题]What Adam Smith said couldbe used to demonstrate the potato#39;sM.general useN.main featuresO.success storyP.bright future5.[单选题]Friedrich Engels#39;s words show that heQ.thought highly of the potatoR.took the potato too seriouslyS.underestimated the role of the potatoT.lacked the basic knowledge of the potato
近与 近与 近与质量为M的物体在光滑的水平面上做简谐振动.振幅是12cm,在距平衡位置6cm处速度为24cm/s近与(1)振动周期 (2)当速度为12cm/s时的位移近与好几年没碰物理 一下子想不起来了近与
- A.2008--the Potato#39;s New Mission
- B.In Praise of the Potato
- C.The History of the Potato
- D.The Potato and Globalization2.[单选题]Europeans began to eatpotatoes in the 18th century because
- E.there was a serious food shortage
- F.they realized that potatoes tasted good
- G.food safety had been greatly improved
- H.eating potatoes had become fashionable3.[单选题]Paragraph 3 mainly describes
- I.why the potato became popular in the north of England
- J.why the potato was important in England#39;s population growth
- K.how the potato contributed to England#39;s industrial development
- L.how the potato helped improve England#39;s working conditions4.[单选题]What Adam Smith said couldbe used to demonstrate the potato#39;s
- M.general use
- N.main features
- O.success story
- P.bright future5.[单选题]Friedrich Engels#39;s words show that he
- Q.thought highly of the potato
- R.took the potato too seriously
- S.underestimated the role of the potato
- T.lacked the basic knowledge of the potato
题目解答
答案
简谐振动的运动方程为位移 X＝Acos(ωt+φ) 速度 V＝-Aωsin(ωt+φ)将已知条件 A＝12 ；X＝6 ；V＝24 代入上述两式,可解得ω＝4/√3（1）振动周期 T＝2π/ω＝√3*π/2（2）当V＝12 时,求得 sin(ωt+φ)＝－1则 ωt+φ＝－π/2,代入位移方程 得X＝0要注意两方程中的正负号的含义,题中没给出,解出的答案就可能在平衡位置的左右两边.