Question

The diameter of metalic ball is 4.2 cm . What is the mass of the ball , if the density of the metalic is 8.9 g per cm³?

Answer 1

DIAMETER=4.2
RADIUS=4.2/2=2.1

$tsa \: of \: sphere = 4\pi {r}^{2}$
=4×22/7×2.1×2.1
=88/7×21/10×21/10
=55.44 cm^2

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Answer 2

✦ Question ✦

The diameter of a metallic ball is 4.2 cm. What is the mass of the ball, if the density of

the metal is 8.9 g per cm?

Answer :-

$\therefore\underline{\boxed{\textsf{M = {\textbf{345.3g}}}}} \qquad\qquad \bigg\lgroup\bold{Mass \ of \ the \ ball} \bigg\rgroup$

Given:

Diameter of a metallic ball is 4.2cm

Density of the metal is 8.9g per cm

Have to find :-

What is the mass of the metallic ball ?

$\Large{\underline{\underline{\bf{Calculations:-}}}}$

As according to the Question :-

Ball is in sphere shape .

So , Volume of sphere is 4/3πr³

So , substituting the values from given

Volume of sphere ↠ 4/3 x 22/7 x ( 2.1 )³

↠ 38.8 cm³

Therefore ,

As we know the formulas of the Density :-

From this we get ,

Mass ↠ Density x Volume

↠ 8.9 x 38.8

↠ 345.3g { The required Answer }