The US quarter has a mass of…?

The US quarter has a mass of 5.67 g and is approximately 1.55 mm thick. (a) How many quarters would have to be stacked to reach 575 ft, the height of the Washington Monument? (b) How much would this stack weigh? (c) How much money would this stack contain? (d) At the beginning of 2007, the national debt was $8.7 trillion. How many stacks like the one described would be necessary to pay off this debt?

a. (1.55 mm)(1 cm/10 mm)(1 in/2.54 cm)(1 ft/12 in) = 0.005 ft. If the Washington Monument is 575 ft, then you’d need 113071 quarters to reach the top.

b. 113071 quarters weighs about 641 kg.

c 113071 quarters is worth $28267.75.

d. You’d need 307771 stacks of quarters to cover the national debt.