力與壓力

現象 公式 應用
力會改變形狀(或運動狀態) 彈簧長度變化∝力的大小
Image Not Showing Possible Reasons
  • The image was uploaded to a note which you don't have access to
  • The note which the image was originally uploaded to has been deleted
Learn More →
摩擦力會防止物體滑動 正向力∝最大靜摩擦力(止滑)
Image Not Showing Possible Reasons
  • The image was uploaded to a note which you don't have access to
  • The note which the image was originally uploaded to has been deleted
Learn More →
力作用在平面上造成壓力 壓力=力/面積
Image Not Showing Possible Reasons
  • The image was uploaded to a note which you don't have access to
  • The note which the image was originally uploaded to has been deleted
Learn More →
物體泡在液體會受到液體壓力 液體壓力=液體密度x深度
Image Not Showing Possible Reasons
  • The image was uploaded to a note which you don't have access to
  • The note which the image was originally uploaded to has been deleted
Learn More →
物體泡在液體會受到向上的浮力 浮力=沉入體積x液體密度
Image Not Showing Possible Reasons
  • The image was uploaded to a note which you don't have access to
  • The note which the image was originally uploaded to has been deleted
Learn More →

浮力

浮力的定義

液體向上支撐物體的力(物體泡到液體)

Image Not Showing Possible Reasons
  • The image was uploaded to a note which you don't have access to
  • The note which the image was originally uploaded to has been deleted
Learn More →

基本計算:力平衡的方式計算

1.浮體:浮力=重力

2.潛體:浮力=重力

3.沉體:浮力=重力-支撐力

<註>物體質量=體積x密度(國二上)

<註>物體密度大於液體,則下沉;密度小於液體,則上浮(國二上)


浮力的公式

浮力受兩個因素影響:物體沉入體積、液體密度

物體沉入體積越多,浮力越大 EX:浮板飄在水上vs浮板壓進水中

液體本身密度越大,浮力越強 EX:浮板壓進水中vs浮板壓進鹽海

Image Not Showing Possible Reasons
  • The image was uploaded to a note which you don't have access to
  • The note which the image was originally uploaded to has been deleted
Learn More →

浮力公式:浮力=沉入體積x液體密度

浮力=沉入體積x液體密度

<註>沉入體積=排開液體體積(國二上)

浮力=排開液體體積x液體密度=排開液體重量


浮力的統整與應用

統整

浮力定義:液體向上支撐物體的力(物體泡到液體) *減輕

一個主要公式:浮力=沉入體積x液體密度 *排開液體重

兩個主要情況:

浮體:浮體的物重=浮力 沉體:沉體的體積=沉入體積

應用

質量50g、體積100cm3物體浮於水(密度1g/cm3),求以下空白處之物理量

(浮力、沉入體積、物體密度)

Image Not Showing Possible Reasons
  • The image was uploaded to a note which you don't have access to
  • The note which the image was originally uploaded to has been deleted
Learn More →

浮力=沉入體積x液體密度 * 浮體物重=浮力

質量20g、體積5cm3物體沉入液體(密度2g/cm3),求以下空白處之物理量

(浮力、沉入體積、物體密度)

Image Not Showing Possible Reasons
  • The image was uploaded to a note which you don't have access to
  • The note which the image was originally uploaded to has been deleted
Learn More →

浮力=沉入體積x液體密度 * 沉入體積=物體體積

質量100g、密度0.5g/cm3的球沉入水(1g/cm3)中,求以下空白處之物理量以及球泡在水面下的比例

Image Not Showing Possible Reasons
  • The image was uploaded to a note which you don't have access to
  • The note which the image was originally uploaded to has been deleted
Learn More →

浮體泡在水面下的比例=浮體密度/液體密度

沉入體積x液體密度=浮體體積x浮體密度
沉入體積/浮體體積=浮體密度/液體密度

密度2g/cm3的物體泡入水(1g/cm3)中彈簧秤顯示減輕10gw,求空白處之物理量

Image Not Showing Possible Reasons
  • The image was uploaded to a note which you don't have access to
  • The note which the image was originally uploaded to has been deleted
Learn More →

浮力=液體向上支撐物體的力(物體泡到液體)=物體減輕重量

密度2g/cm3的物體投入密度0.5g/cm3的液體中,液體排開了100g,求空白處之物理量

Image Not Showing Possible Reasons
  • The image was uploaded to a note which you don't have access to
  • The note which the image was originally uploaded to has been deleted
Learn More →

浮力=沉入體積x液體密度=排開液體體積x液體密度=排開液體重

補充:沉船時,浮力變(大/小),物體沉入體積或液體排開體積變(大/小) * 易錯

Image Not Showing Possible Reasons
  • The image was uploaded to a note which you don't have access to
  • The note which the image was originally uploaded to has been deleted
Learn More →

補充:比較誰的浮力大

浮力=沉入體積x液體密度 * 浮體:浮力=物重

Image Not Showing Possible Reasons
  • The image was uploaded to a note which you don't have access to
  • The note which the image was originally uploaded to has been deleted
Learn More →

Image Not Showing Possible Reasons
  • The image was uploaded to a note which you don't have access to
  • The note which the image was originally uploaded to has been deleted
Learn More →

Image Not Showing Possible Reasons
  • The image was uploaded to a note which you don't have access to
  • The note which the image was originally uploaded to has been deleted
Learn More →

補充:浮力=沉入體積x液體密度 浮力變化=沉入體積變化x液體密度

Image Not Showing Possible Reasons
  • The image was uploaded to a note which you don't have access to
  • The note which the image was originally uploaded to has been deleted
Learn More →