<span>дано:</span>
<em><span>ρ</span></em><span>т=7800кг/м3</span>
<em><span>ρ</span></em><span>1=1000 кг/м3</span>
<span>Р1=7000Н</span>
<span>m</span><span>-?</span>
<span>P</span><span>2-</span><span>P</span><span>1=</span><span>Fa</span><span>, </span><span>Fa</span><span>=</span><em><span> ρ</span></em><span>gV</span><span>т, <span> </span>Р2=</span><span>mg</span><span>, <span> </span></span><span>mg</span><span>- </span><span>P</span><span>1=</span><em><span> ρ</span></em><span>gV</span><span>т, </span><span>V</span><span>т=</span><span>m</span><span>/</span><em><span> ρ</span></em><span>т, </span>
<span>mg</span><span>-Р1=</span><em><span>ρ</span></em><span>g</span><span>m</span><span>/</span><em><span> ρт</span></em>
<span><span> </span></span>
<span>mg</span><span>-</span><em><span>ρ</span></em><span>g</span><span>m</span><span>/</span><em><span> ρт=Р1</span></em>
<span> <span> </span></span>
<span>m</span><span>(</span><span>g</span><span>-</span>
<em><span> ρ</span></em><span>g</span><span>/</span><em><span> ρ g / ρ т)=P1</span></em><span>,</span>
<span>m= P</span><span>1</span><span>/</span><span>(</span><span>g</span><span>-</span><em><span> ρ</span></em><span>g</span><span>/</span><em><span> ρ</span></em><span>т)</span><span>,<span> </span>m=7000/(10-1000*10/7800)=803,67кг=</span>
<span>804кг</span>