Completely 82545

A granite cube with an edge length of 1 dm and a weight of 2.5 kg is completely immersed in a container of water. How much buoyancy does it lighten? How much pressure does the cube exert on the bottom of the container?

Correct answer:

F₁ =  10 N
F₂ =  15 N

Step-by-step explanation:

$$\begin{gathered} a=1\text{dm}\to \text{m}=1:10\text{m}=0.1\text{m} \\ m=2.5\text{kg} \\ {\rho }_1=1000{\text{kg/m}}^3 \\ g=10{\text{m/s}}^2 \\ V=a^3=0.1^3=\frac{1}{1000}=0.001{\text{m}}^3 \\ G=m\cdot g=2.5\cdot 10=25\text{N} \\ {m}_2={\rho }_1\cdot V=1000\cdot 0.001=1\text{kg} \\ {F}_1=m_2\cdot g=1\cdot 10=10\text{N} \end{gathered}$$

$F_2=G-F_1=25-10=15\text{N}$

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