Question

SOMEONE PLEASE HELP

Answer 1

6. 7870 kg/m³ (3 s.f.)

7. 33.4 g (3 s.f.)

8. 12600 kg/m³ (3 s.f.)

Step-by-step 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

`= 8.16 * 10^( - 6) \: kg`

`\boxed{density = (mass)/(volume) }`

Density of iron bar

`= (0.0642)/(8.16 * 10^( - 6) )`

= 7870 kg/m³ (3 s.f.)

7.

`\boxed{mass = density \: * volume}`

Mass

= 1.16 ×28.8

= 33.408 g

= 33.4 g (3 s.f.)

8. Volume of brick

= 12 cm³

`= 12 * 10^( - 6) \: m^(3) \\ = 1.2 * 10^( - 5) \: m ^(3)`

Mass of brick

= 151 g

= 151 ÷ 1000 kg

= 0.151 kg

Density of brick

= mass ÷ volume

`= \frac{0.151} {1.25 * 10^( - 5) } \\ = 12600 \: kg/ {m}^(3)`

(3 s.f.)