asked 36.5k views
5 votes
Q3.

Here is a frustum of a cone.
7.2 cm
3.2cm
3.2 cm
Volume of sphere w
The diagram shows that the frustum is made by removing a cone with height 3.2 cm from
a solid cone with height 6.4 cm and base diameter 7.2 cm.
Solid S
Volume of cone=
The frustum is joined to a solid hemisphere of diameter 7.2 cm to form the sollid S shown
below.
The density of the frustum is 2.4 g/cm³
The density of the hemisphere is 4.8 g/cm³
Calculate the average density of solid S
<--72cm
3.2cm

1 Answer

4 votes

To calculate the average density of solid S, we need to first find the total mass of solid S and then divide it by the total volume of solid S.

Let's start by finding the volumes of the frustum, cone, and hemisphere.

Volume of cone = (1/3)πr²h = (1/3)π(3.6)²(6.4) ≈ 82.99 cm³

Volume of frustum = (1/3)πh (r₁² + r₂² + r₁r₂)

= (1/3)π(3.2)(3.6² + 3.2² + 3.2*3.6) ≈ 43.97 cm³

Volume of hemisphere = (2/3)πr³ = (2/3)π(3.6/2)³ ≈ 22.62 cm³

Total volume of solid S = volume of cone + volume of frustum + volume of hemisphere

≈ 82.99 + 43.97 + 22.62

≈ 149.58 cm³

Next, we can find the masses of the frustum and hemisphere using their densities and volumes:

Mass of frustum = density × volume = 2.4 × 43.97 ≈ 105.53 g

Mass of hemisphere = density × volume = 4.8 × 22.62 ≈ 108.50 g

To find the mass of the cone, we need to subtract the mass of the frustum from the mass of the solid cone:

Mass of cone = density × volume of cone - mass of frustum

= 2.4 × 82.99 - 105.53

≈ 100.60 g

Total mass of solid S = mass of cone + mass of frustum + mass of hemisphere

≈ 100.60 + 105.53 + 108.50

≈ 314.63 g

Finally, we can calculate the average density of solid S by dividing the total mass by the total volume:

Average density of solid S = total mass / total volume

≈ 314.63 / 149.58

≈ 2.104 g/cm³

Therefore, the average density of solid S is approximately 2.104 g/cm³.

answered
User Djabx
by
7.6k points
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