How many grams of aluminum are required to give a total dislocation length of 3,000 miles (enough to stretch from New York City to Los Angeles assuming you could align all the dislocations into a single line like a string). Assume the dislocation density of aluminum is 1010cm/cm3.

0.13 g

Explanation:

mass of aluminum required = ( Dislocation length) / ( Dislocation density) × (density of metal)

3000 miles to cm (  1 mile = 160934 cm) = 3000 miles ×  160934 cm / 1 mile = 482802000 cm

density of Aluminium = 2.7 g /cm³

dislocation density of aluminum = 10¹⁰ cm³

mass of aluminum required = (482802000 cm × 2.7 g/cm³) / 10¹⁰ cm³ = 0.13 g