Question

Find the weight of a hollow sphere of metal having internal and external diameter as 20 cm and 22 cm respectively if 1 cm cube of metal weights 21 gram

Answer 1

volume of sphere is

$\frac{4}{3} \pi \: {r}^{3}$

D = 22 cm, R = 11cm

d = 20cm, r = 10cm

volume of metalic sphere is

$\frac{4}{3} \pi {r}^{3} - \frac{4}{3} \pi {r}^{3}$

then,

vol. of metallic sphere × 21g =

28.37 kg @ns...