中考物理基础常识（五）:压强和浮力

Basic Physics Knowledge for the Senior High School Entrance Examination (Part Five): Pressure and Buoyancy

李宏 湖北省十堰市郧阳中学

Li Hong Yunyang High School， Shiyan City， Hubei Province

第九章 压强-[中考物理基础常识]

Chapter 9: Pressure [Basic Knowledge of Physics for the High School Entrance Exam]

裁剪

54．影响压力作用为止的身分：（1）压力大小；（2）受力面积大小

伸开剩余90%

Factors affecting pressure effects: Magnitude of force (pressure); Area of contact (surface area)

55．压强的盘算公式：p=F/S

Pressure calculation formula:p=F/S (Pressure = Force per unit area)

56．液体压强的脾气：

Characteristics of liquid pressure:

（1）液体里面朝各个目的齐有压强；

Liquids exert pressure in all directions internally;

（2）在归拢深度液体向各个目的的压强卓绝；

At the same depth， pressure is equal in all directions;

（3）在同种液体中，深度越深，液体压强越大；

In the same liquid， pressure increases with depth;

（4）在深度调换期，液体的密度越大，开云液体压强越大。

At the same depth， pressure increases with liquid density.

57．液体压强的盘算：P＝ρgh

Liquid pressure formula:P=ρgh

液体的压强只与液体的密度和浸入液体的深度推敲。

Liquid pressure depends only on liquid density ( ρρ ) and depth ( hh ).

58．阐发大气压存在的推行：马德堡半球推行(解释大气压强的存在)。

Experiments confirming atmospheric pressure:Magdeburg hemispheres experiment (demonstrates atmospheric pressure existence).

测定大气压值的推行是：托里拆利推行。

1尺度大气压为760mmHg，即1．013×105Pa。

Torricelli's experiment (measures atmospheric pressure).1 standard atmospheric pressure = 760 mmHg =1.013×10⁵Pa.

59．大气压与海拔高度的联系：大气压随高度的增多而减小。

Relationship between atmospheric pressure and altitude:Atmospheric pressure decreases with increasing altitude.

60．流体压强与流速的联系：在气体和液体中，流速越大的位置压强越小(伯努利旨趣)。

Relationship between fluid pressure and flow speed:In gases and liquids， faster flow speed results in lower pressure (Bernoulli's principle).

第十章 浮力-[中考物理基础常识]

Chapter 10 Buoyancy - [Basic Knowledge of Physics for High School Entrance Examination]

61．浮力产生的原因：浮力是由液体（或气体）对物体进取和向下的压力差产生的。

Cause of buoyant force: Buoyant force is produced by the pressure difference between the upward and downward pressures exerted on an object by a liquid (or gas).

浮力的目的：竖直进取。

Direction of buoyant force: Vertically upward.

裁剪

62．阿基米德旨趣：浸在液体中的物体所受的浮力，大小就是它排开液体所受的重力。即F浮＝G排＝M排g=ρ液gV排。

Archimedes' Principle: The buoyant force acting on an object immersed in a liquid is equal in magnitude to the weight of the liquid displaced by the object. That is， F buoy =G displaced =ρliquid gV displaced .

闪耀：浸在液体中的物体所受的浮力只与液体的密度和排开液体的体积推敲；浸没在液体中的物体所受的浮力与浸没的深度无关。

Note: The buoyant force on an object immersed in a liquid is only related to the density of the liquid and the volume of the displaced liquid; the buoyant force on an object fully submerged in a liquid has no relation to the depth of submersion.

63．汽船是应用飘摇的要求F浮＝G物来责任的。

Ships work by making use of the floating condition:F buoy =G object.

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潜水艇是靠调动自己重力来驱散上浮和下千里的。

Submarines achieve ascending and descending by changing their own gravity.

64．求浮力的几种重要：

Several methods for calculating buoyant force:

(1)称重法： F浮＝G－F拉

Weighing method: F buoy =G−F tension

(2)压力差法：F浮＝F进取－F向下

Pressure difference method: F buoy =F up −F down

(3)阿基米德旨趣法：F浮＝ρ液gV排

Archimedes' principle method: F buoy=ρ liquid gV displaced

(4)飘摇或悬浮法：F浮＝G物

Floating or suspending method: F buoy =G object

Explorer of Innovative Thinking

Author: Li Hong

Yunyang High School， Shiyan City， Hubei Province

February 4， 2026

发布于：湖北省