1) l = 0,4 m = 4 Ā· 10ā»Ā¹ m
V = lĀ³ = (4 Ā· 10ā»Ā¹)Ā³ = 4Ā³ Ā· 10ā»Ā³ mĀ³ = 64 Ā· 10ā»Ā³ mĀ³
marmura are densitatea de aproximativ Ļ = 2,65 kg/cmĀ³ = 2,65 Ā· 10Ā³ / (10ā»Ā²)Ā³ = 2,65 Ā· 10Ā³ / 10ā»ā¶ = 2,65 Ā· 10ā¹ g/mĀ³
Ļ = m / V ā m = Ļ Ā· V
m = 2,65 Ā· 10ā¹ Ā· 64 Ā· 10ā»Ā³ = 169,6 Ā· 10ā¶ g = 169,6 Ā· 10Ā³ kg = 169,6 t
2) m = 540 kg = 540 Ā· 10Ā³ g
Ļ = 2,7 g/cmĀ³ = 2,7 / (10ā»Ā²)Ā³ = 2,7 / 10ā»ā¶ g/mĀ³
Ļ = m / V ā V = m / Ļ
V = (540 Ā· 10Ā³)/ (2,7 / 10ā»ā¶) = 540 Ā· 10Ā³ Ā· 10ā¶ / 2,7 = 200 Ā· 10Ā³ = 2 Ā· 10āµ mĀ³
3) V = 4 dmĀ² = 4 Ā· (10ā»Ā¹)Ā² = 4 Ā· 10ā»Ā¹ mĀ²
Ļ = 8,94 g/cmĀ³ = 8,94 / (10ā»Ā²)Ā³ = 8,94 / 10ā»ā¶ g/mĀ³
Ļ = m / V ā m = Ļ Ā· V
m = (8,94 / 10ā»ā¶) Ā· 4 Ā· 10ā»Ā¹ = 35,76 Ā· 10āµ g = 35,76 Ā·10Ā² kg = 3576 kg = 3,576 t