Answer:
6. 7870 kg/m³ (3 s.f.)
7. 33.4 g (3 s.f.)
8. 12600 kg/m³ (3 s.f.)
Explanation:
6. The SI unit for density is kg/m³. Thus convert the mass to Kg and volume to m³ first.
1 kg= 1000g
1m³= 1 ×10⁶ cm³
Mass of iron bar
= 64.2g
= 64.2 ÷1000 kg
= 0.0642 kg
Volume of iron bar
= 8.16 cm³
= 8.16 ÷ 10⁶
[tex] = 8.16 \times 10^{ - 6} \: kg[/tex]
[tex]\boxed{density = \frac{mass}{volume} }[/tex]
Density of iron bar
[tex] = \frac{0.0642}{8.16 \times 10^{ - 6} } [/tex]
= 7870 kg/m³ (3 s.f.)
7.
[tex]\boxed{mass = density \: \times volume}[/tex]
Mass
= 1.16 ×28.8
= 33.408 g
= 33.4 g (3 s.f.)
8. Volume of brick
= 12 cm³
[tex] = 12 \times 10^{ - 6} \: m^{3} \\ = 1.2 \times 10^{ - 5} \: m ^{3} [/tex]
Mass of brick
= 151 g
= 151 ÷ 1000 kg
= 0.151 kg
Density of brick
= mass ÷ volume
[tex] = \frac{0.151} {1.25 \times 10^{ - 5} } \\ = 12600 \: kg/ {m}^{3} [/tex]
(3 s.f.)
