Question

a certain material has a mass of 100 g while occupying 40 cm³ of space. what is this material?
○ gold
○ lead
○ iron
○ rock
○ wood

Explanation:

Step1: Calculate density

Density formula: $
ho = \frac{m}{V}$, where $m = 100\ g$, $V = 40\ cm^3$.
$
ho = \frac{100}{40} = 2.5\ g/cm^3$.

Step2: Compare with known densities

• Gold: ~19.3 g/cm³, Lead: ~11.3 g/cm³, Iron: ~7.9 g/cm³, Rock: ~2 - 3 g/cm³, Wood: <1 g/cm³. 2.5 g/cm³ matches rock's density range.

Answer:

rock (from the options: rock)