A medicine capsule is in the shape of a cylinder with two hemispheres stuck to each of its ends (see Fig. 13.10). The length of the entire capsule is 14 mm and the diameter of the capsule is 5 mm. Find its surface area
According to the question,
Radius (r) of cylindrical part = Radius (r) of hemispherical part
= 
= 
Length of cylindrical part (h) = Length of the entire capsule - 2 × r
= 14 - 5
= 9 cm
Surface area of capsule = 2×CSA of hemispherical part + CSA of cylindrical part
= 2 * 2πr2 + 2πrh
= 4π (
)2 + 2π (
) (9)
= 25π + 45π
= 70π
= 70 * 
= 220 mm2
20