The solar

The solar heating tank has the shape of a rotating cylinder. When the tank is in a horizontal position, the water in the tank wets 4/5 of each tank base. If we place the tank in a vertical position, the water in the tank will reach up to 1.2 m. Calculate the length of the tank.

Correct answer:

x =  1.5 m

Step-by-step explanation:

$$\begin{gathered} h_2=1.2\text{m} \\ {V}_1=\frac{4}{5}\cdot S\cdot x \\ {V}_2=S\cdot h_2=S\cdot 1.2=0 \\ {V}_1=V_2 \\ \frac{4}{5}\cdot S\cdot x=S\cdot h_2 \\ \frac{4}{5}\cdot x=h_2=1.2=\frac{6}{5} \\ x=h_2\cdot \frac{5}{4}=1.2\cdot \frac{5}{4}=\frac{3}{2}\text{m}=1.5\text{m} \end{gathered}$$

Try another example