Question

In the diagram given below, a tilted right circular cylindrical vessel with a base diameter of 7 cm contains a liquid. When placed vertically, the height of the liquid in the vessel is the mean of two heights shown in the diagram. Find the area of the wet surface when the cylinder is placed vertically on a horizontal surface. `("Use"  π = 22/7)`.

Answer 1

When vertically placed,

Height of liquid (h) = `(1 + 6)/2 = 7/2` cm

Diameter of base = 7 cm

Radius (r) = `7/2` cm

Area of wet surface = πr² + 2πrh

= πr(r + 2h)

= `22/7 xx 7/2(7/2 + 2 xx 7/2)`

= 11 × (3.5 + 7)

= 11 × 10.5

= 115.5 cm²

Hence, area of wet surface is 115.5 cm².