Question

A spherical ball of lead has a diameter of 2.5 cm . What is the mass of the sphere if lead has a density of 11.34 g/cm3? (The volume of a sphere is (43)πr3 where r is the radius.)

Answer 1

mass = volume x density

volume = πr²
since Diameter = 2.5 cm
then radius = 1.25cm

∴ volume = π x (1.25cm)³
≈ 6.1359 cm³

Thus mass = 6.1359 cm³ x 11.34 g / cm³
= 69.58 g

Answer 2

Answer : The mass of sphere is 92.727 grams.

Explanation :

To calculate the volume of sphere, we use the formula:

`V=(4)/(3)\pi r^3` .....(1)

where,

r = radius of sphere

Given :

Diameter of sphere = 2.5 cm

Radius of sphere =
`(Diameter)/(2)=(2.5cm)/(2)=1.25cm`

Now put all the given values in the above formula (1), we get:

`V=(4)/(3)* 3.14* (1.25cm)^3`

`V=8.177cm^3`

To calculate mass of a substance, we use the equation:

`Density=(Mass)/(Volume)` .....(2)

Putting values in above equation (2), we get:

`11.34g/cm^3=(Mass)/(8.177cm^3)`

`Mass=92.727g`

Hence, the mass of sphere is 92.727 grams.