Uses of aluminium
3 marks · NormalA company is designing lightweight power cables using aluminium. Each cable must have a mass of no more than 2.70 kg per metre. The density of pure aluminium is 2.70 g/cm³.
Calculate the volume, in cm³, of aluminium in 1 metre of this cable.
Explain why using aluminium, rather than copper (8 = 8.96 g/cm³), is suitable for lightweight cables.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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(a) 1000 cm³
(b) Aluminium is much less dense than copper, so for the same mass you can use a larger volume, making the cable lighter.
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Marking points
M1 (a) · 1 mark · Uses the correct formula: volume = mass ÷ density, with correct units. (follow-through)
A1 (a) · 1 mark · Correct calculation: 2.70 kg = 2700 g, so 2700 g ÷ 2.70 g/cm³ = 1000 cm³.
B1 (b) · 1 mark · Explains that aluminium's lower density makes it better for lightweight applications than copper.
Worked solution
a) First, convert mass to grams: 2.70 kg = 2700 g.
Volume = mass ÷ density = 2700 g ÷ 2.70 g/cm³ = 1000 cm³
b) Aluminium is less dense than copper (2.70 g/cm³ < 8.96 g/cm³), so it is more suitable for lightweight cables.