Bài 4: Khối lượng riêng. Áp suất chất lỏng
Hướng dẫn giải Câu hỏi 4 (Trang 63 SGK Vật lý 10, Bộ Cánh diều)
<p>Chứng tỏ rằng ch&ecirc;nh lệch &aacute;p suất &Delta;p giữa hai điểm trong chất lỏng tỉ lệ thuận với ch&ecirc;nh lệch độ s&acirc;u &Delta;h của hai điểm đ&oacute;</p> <p><strong>Lời giải:</strong></p> <p>&Aacute;p suất chất lỏng tại điểm c&oacute; độ s&acirc;u h<sub>1</sub>:&nbsp;<span id="MathJax-Element-1-Frame" class="mjx-chtml MathJax_CHTML" style="box-sizing: border-box; display: inline-block; line-height: 0; text-indent: 0px; text-align: left; text-transform: none; font-style: normal; font-weight: normal; font-size: 21.78px; letter-spacing: normal; overflow-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; margin: 0px; padding: 1px 0px; position: relative;" tabindex="0" role="presentation" data-mathml="&lt;math xmlns=&quot;http://www.w3.org/1998/Math/MathML&quot;&gt;&lt;msub&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/msub&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;mi&gt;o&lt;/mi&gt;&lt;/msub&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mi&gt;&amp;#x3C1;&lt;/mi&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;msub&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/msub&gt;&lt;/math&gt;"><span id="MJXc-Node-1" class="mjx-math" aria-hidden="true"><span id="MJXc-Node-2" class="mjx-mrow"><span id="MJXc-Node-3" class="mjx-msub"><span class="mjx-base"><span id="MJXc-Node-4" class="mjx-mi"></span></span></span></span></span><math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>p</mi><mn>1</mn></msub><mo>=</mo><msub><mi>p</mi><mi>o</mi></msub><mo>+</mo><mi>&rho;</mi><mi>g</mi><msub><mi>h</mi><mn>1</mn></msub></math><math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mn></mn></msub></math></span></p> <p>&Aacute;p suất chất lỏng tại điểm c&oacute; độ s&acirc;u h<sub>2</sub>:&nbsp;<span id="MathJax-Element-2-Frame" class="mjx-chtml MathJax_CHTML" style="box-sizing: border-box; display: inline-block; line-height: 0; text-indent: 0px; text-align: left; text-transform: none; font-style: normal; font-weight: normal; font-size: 21.78px; letter-spacing: normal; overflow-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; margin: 0px; padding: 1px 0px; position: relative;" tabindex="0" role="presentation" data-mathml="&lt;math xmlns=&quot;http://www.w3.org/1998/Math/MathML&quot;&gt;&lt;msub&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;mi&gt;o&lt;/mi&gt;&lt;/msub&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mi&gt;&amp;#x3C1;&lt;/mi&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;msub&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;/math&gt;"><span id="MJXc-Node-16" class="mjx-math" aria-hidden="true"><span id="MJXc-Node-17" class="mjx-mrow"><span id="MJXc-Node-18" class="mjx-msub"><span class="mjx-base"><span id="MJXc-Node-19" class="mjx-mi"></span></span></span></span></span><math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mi>p</mi><mn>2</mn></msub><mo>=</mo><msub><mi>p</mi><mi>o</mi></msub><mo>+</mo><mi>&rho;</mi><mi>g</mi><msub><mi>h</mi><mn>2</mn></msub></math><math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mn></mn></msub></math></span></p> <p>Độ ch&ecirc;nh lệch &aacute;p suất giữa 2 điểm tr&ecirc;n:</p> <p><span id="MathJax-Element-3-Frame" class="mjx-chtml MathJax_CHTML" style="box-sizing: border-box; display: inline-block; line-height: 0; text-indent: 0px; text-align: left; text-transform: none; font-style: normal; font-weight: normal; font-size: 21.78px; letter-spacing: normal; overflow-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; margin: 0px; padding: 1px 0px; position: relative;" tabindex="0" role="presentation" data-mathml="&lt;math xmlns=&quot;http://www.w3.org/1998/Math/MathML&quot;&gt;&lt;mi&gt;&amp;#x394;&lt;/mi&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;mo&gt;&amp;#x2212;&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/msub&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mfenced&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;mi&gt;o&lt;/mi&gt;&lt;/msub&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mi&gt;&amp;#x3C1;&lt;/mi&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;msub&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/mfenced&gt;&lt;mo&gt;&amp;#x2212;&lt;/mo&gt;&lt;mfenced&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;mi&gt;o&lt;/mi&gt;&lt;/msub&gt;&lt;mo&gt;+&lt;/mo&gt;&lt;mi&gt;&amp;#x3C1;&lt;/mi&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;msub&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/mfenced&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mi&gt;&amp;#x3C1;&lt;/mi&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;mfenced&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;mo&gt;&amp;#x2212;&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/mfenced&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;mi&gt;&amp;#x3C1;&lt;/mi&gt;&lt;mi&gt;g&lt;/mi&gt;&lt;mi&gt;&amp;#x394;&lt;/mi&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;/math&gt;"><span id="MJXc-Node-31" class="mjx-math" aria-hidden="true"><span id="MJXc-Node-32" class="mjx-mrow"><span id="MJXc-Node-33" class="mjx-mi"></span></span></span><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>&Delta;</mi><mi>p</mi><mo>=</mo><msub><mi>p</mi><mn>2</mn></msub><mo>&minus;</mo><msub><mi>p</mi><mn>1</mn></msub><mo>=</mo><mo>(</mo><msub><mi>p</mi><mi>o</mi></msub><mo>+</mo><mi>&rho;</mi><mi>g</mi><msub><mi>h</mi><mn>2</mn></msub><mo>)</mo><mo>&minus;</mo><mo>(</mo><msub><mi>p</mi><mi>o</mi></msub><mo>+</mo><mi>&rho;</mi><mi>g</mi><msub><mi>h</mi><mn>1</mn></msub><mo>)</mo><mo>=</mo><mi>&rho;</mi><mi>g</mi><mo>(</mo><msub><mi>h</mi><mn>2</mn></msub><mo>&minus;</mo><msub><mi>h</mi><mn>1</mn></msub><mo>)</mo><mo>=</mo><mi>&rho;</mi><mi>g</mi><mi>&Delta;</mi><mi>h</mi></math><math xmlns="http://www.w3.org/1998/Math/MathML"><mi></mi></math></span></p> <p>Chứng tỏ rằng ch&ecirc;nh lệch &aacute;p suất&nbsp;<span id="MathJax-Element-4-Frame" class="mjx-chtml MathJax_CHTML" style="box-sizing: border-box; display: inline-block; line-height: 0; text-indent: 0px; text-align: left; text-transform: none; font-style: normal; font-weight: normal; font-size: 21.78px; letter-spacing: normal; overflow-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; margin: 0px; padding: 1px 0px; position: relative;" tabindex="0" role="presentation" data-mathml="&lt;math xmlns=&quot;http://www.w3.org/1998/Math/MathML&quot;&gt;&lt;mi&gt;&amp;#x394;&lt;/mi&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/math&gt;"><span id="MJXc-Node-90" class="mjx-math" aria-hidden="true"><span id="MJXc-Node-91" class="mjx-mrow"><span id="MJXc-Node-92" class="mjx-mi"></span></span></span><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>&Delta;</mi><mi>p</mi></math><math xmlns="http://www.w3.org/1998/Math/MathML"><mi></mi></math></span>&nbsp;giữa hai điểm trong chất lỏng tỉ lệ thuận với ch&ecirc;nh lệch độ s&acirc;u</p> <p>&nbsp;<span id="MathJax-Element-5-Frame" class="mjx-chtml MathJax_CHTML" style="box-sizing: border-box; display: inline-block; line-height: 0; text-indent: 0px; text-align: left; text-transform: none; font-style: normal; font-weight: normal; font-size: 21.78px; letter-spacing: normal; overflow-wrap: normal; word-spacing: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; margin: 0px; padding: 1px 0px; position: relative;" tabindex="0" role="presentation" data-mathml="&lt;math xmlns=&quot;http://www.w3.org/1998/Math/MathML&quot;&gt;&lt;mi&gt;&amp;#x394;&lt;/mi&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;mo&gt;=&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/msub&gt;&lt;mo&gt;&amp;#x2212;&lt;/mo&gt;&lt;msub&gt;&lt;mi&gt;h&lt;/mi&gt;&lt;mn&gt;1&lt;/mn&gt;&lt;/msub&gt;&lt;/math&gt;"><span id="MJXc-Node-94" class="mjx-math" aria-hidden="true"><span id="MJXc-Node-95" class="mjx-mrow"><span id="MJXc-Node-96" class="mjx-mi"></span></span></span><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>&Delta;</mi><mi>h</mi><mo>=</mo><msub><mi>h</mi><mn>2</mn></msub><mo>&minus;</mo><msub><mi>h</mi><mn>1</mn></msub></math><math xmlns="http://www.w3.org/1998/Math/MathML"><msub><mn></mn></msub></math></span>&nbsp;của hai điểm đ&oacute;.</p>
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