Chapter 1, Problem 1.95E

A person weighed 15 pennies on a balance and recorded the following masses: 3.112 g 3.109 g 3.059 g 2.467 g 3.079 g 2.518 g 3.129 g 2.545 g 3.050 g 3.053 g 3.054 g 3.072 g 3.081 g 3.131 g 3.064 g Curious about the results, he looked at the dates on each penny. Two of the light pennies were minted in 1983 and one in 1982. The dates on the 12 heavier pennies ranged from 1970 to 1982. Two of the 12 heavier pennies were minted in 1982. a. Do you think the Bureau of the Mint changed the way it made pennies? Explain. b. The person calculated the average mass of the 12 heavy pennies. He expressed this average as 3.0828 g 0.0482 g. What is wrong with the numbers in this result, and how should the value be expressed?

A sample of a bright blue mineral was weighed in air, then weighed again while suspended in water. An object is buoyed up by the mass of the fluid displaced by the object. In air, the mineral weighed 7.35 g; in water, it weighed 5.40 g. The densities of air and water are 1.205 g/L and 0.9982 g/cm3, respectively. What is the density of the mineral?

A sample of vermilion-colored mineral was weighed in air, then weighed again while suspended in water. An object is buoyed up by the mass of the fluid displaced by the object. In air, the mineral weighed 18.49 g; in water, it weighed 16.21 g. The densities of air and water are 1.205 g/L and 0.9982 g/cm3, respectively. What is the density of the mineral?