Question

A fish tank is in the shape of an open glass cuboid 30cm deep with a base 16cm by 17cm,thesr measurements being external. If the glass is 0.5cm thick and it's density is 3g/cm3 find;
a) the capacity of the tank in litres
b) the mass of the tank in kg

Answer 1

a) The internal measurements of the fish tank can be found by subtracting twice the thickness of the glass from the external measurements:

Internal length = 16cm - 2(0.5cm) = 15cm
Internal width = 17cm - 2(0.5cm) = 16cm
Internal height = 30cm - 2(0.5cm) = 29cm

The capacity of the tank in liters is calculated by multiplying the internal length, width, and height together and then dividing by 1000 to convert to liters:

Capacity = (15cm x 16cm x 29cm) / 1000 = 7.68 liters

b) The volume of the glass can be found by subtracting the internal volume from the external volume:

External volume = 16cm x 17cm x 30cm = 8,160 cm^3
Internal volume = 15cm x 16cm x 29cm = 6,720 cm^3

Glass volume = External volume - Internal volume = 1,440 cm^3

The mass of the glass can be found by multiplying the glass volume by its density:

Mass = 1,440 cm^3 x 3 g/cm^3 = 4,320 g

Converting to kilograms:

Mass = 4,320 g / 1000 = 4.32 kg

Therefore, the mass of the tank is 4.32 kg.