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 cm3​

Answer 1

Given

✭ Diameter of a metallic ball is 4.2 cm

✭ Density of the metal is 8.9 g/cm³

To Find

◈ Mass of the ball?

Solution

Concept

We shall here find the volume of the ball first, then we know the formula to find Density which is equal to the quotient of the Mass & Volume, substituting the values would get us our Answer!!

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Radius of the ball is given by,

➝ Radius = Diameter/2

Substituting the given values,

➝ Radius = 4.2/2

➝ Radius = 2.1 cm

So now the volume of a sphere (ball) is given by,

➝ Volume{Sphere} = 4/3 πr³

• π = 22/7
• R = 2.1 cm

Substituting the values,

➳ Volume = 4/3 πr³

➳ Volume = 4/3 × 22/7 × 2.1³

➳ Volume = 4/3 × 22/7 × 9.261

➳ Volume = 38.808 cm³

So then Density is given by,

»» Density = Mass/Volume

»» Mass = Density × Volume

• Density = 8.9 g/cm³
• Volume = 38.808 cm³

»» Mass = 8.9 × 38.808

»» Mass = 345.3912 g

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Answer 2

Step-by-step explanation:

Given:

diameter: 4.2cm

density: 8.9 g/cm3

mass:?

solution:

diameter:4.2/2 =2.1cm

volume: 4/3πr3

4 ×22 ×2.1 ×2.1×2.1

3. 7

4 ×22×21×21×21

3. 7. 10. 10. 10

11×1×21×21

5. 5. 5

=4851

125

=38.808cm3

mass=density×volume

=8.9×38.808

=345.3912g

hope it's helpful...