Question

the diameter of a metallic ball is 4.2 centimetre what is the mass of the ball is the density of the meter is 8.9 gram per centimetre cube​

Answer 1

HELLO DEAR FRIEND

Given,

the diameter of a metallic ball = 4.2 cm

so, radius =

$\large{ \frac{ \large{4.2}}{ \large{2}} }$= 2.1 cm

volume of metallic ball =

$\large{ \frac{ \large{4}}{ \large{3}}\ \pi {r}^{2} }$

$\large{ \frac{ \large{4}}{ \large{3}}\ \times \frac{ \large{22}}{ \large{7}} \times {2.1}^{2} }$

$\large{ \frac{ \large{4}}{ \large{3}}\ \times \frac{ \large{22}}{ \large{7}} \times {2.1} \times 2.1\times 2.1}$

= 4 × 22 × 2.1 × 2.1

$\large \boxed{ {388.08cm}^{3} }$

$\large \boxed{ {388cm}^{3} }$approx.

Also given,

density = $\large{ \frac{ \large{volume}}{ \large{mass}} }$

So,
Mass = $\large{ \frac{ \large{volume}}{ \large{density}} }$
= $\large{ \frac{ \large{388}}{ \large{8.9}} }$

= $\large \boxed{ { 43.6 gram}}$approx.

HOPE IT HELPS YOU DEAR FRIEND THANKS

Answer 2

Radius of the metallic ball = 4.2/2

= 2.1 cm

Volume of the metallic ball = 4/3 pie × r³

= 4/3 × 22/7 × (2.1)³

= 4/3 × 22/7 × 2.1 × 2.1 × 2.1

= 4 × 22 × 2.1 × 2.1

= 388.08 cm³

We know that,

Density = Volume / Mass

Therefore,

Mass = Volume / Density

= 388.08 / 8.9

= 43.6044944 grams

Mass = 43.6044944 grams