Weight

1. Weight In the imperial system

2. Pounds • The pound as a unit of weight dates back at least as far as the time of the Romans • the symbol for one pound is 1 lb. This symbol is an abbreviation of the Latin word libra—the word for a set of scales used for weighing. One pound is defined as exactly 0.453 592 37 kg.

3. Scales • a set of scales is considered to be any instrument that measures weight (mass). • An instrument that measures weight does not have to be made up of two pans connected to a bar • For example, bathroom scales

4. ounce (oz) There are 16 oz in 1 lb. 1 lb = 16 oz The Roman pound was divided into 12 parts. The Latin word uncia for “twelfth part,” as you will recall, gave the word inch. It also gives the English word ounce. The troy pound, used for precious metals, such as gold and silver, still has 12 ounces. However, the modern pound commonly used for weight (mass) is divided into 16 ounces!

5. Nutritionists recommend active teenage girls eat 5 oz of protein each day. How many pounds of protein would this recommendation be over a 30-day month?

6. Krysta’s baby was 6 lb 7 oz when she was born. Altogether, how many ounces did the newborn weigh?

7. Large Masses • in the metric system for large masses we measure in tonnes. 1 t = 1000 kg • In the imperial system, large weights such as the weight of sand being hauled in a truck, is measured in tons. There are short tons and long tons. The British defined the ton as equal to 160 stone when they considered the stone as the basic unit of weight. One stone equals 14 lb. Therefore, the British ton, now also known as the long ton, is equal to 2240 lb. 1 ton = 2000 lb 1 short ton = 2000 lb 1 long ton = 2240 lb

8. Since 1 kg is about 2.2 lb, what would an approximation of the metric tonne be in pounds? Which is a metric tonne closer to—a short ton or a long ton?

9. Mr. Watnee hauls gravel. He estimates that 1 yd3 weighs 3000 lb. How many tons (short) would a 5-yd3 load of gravel weigh?

10. Sergey loaded 200 bushels of wheat into the box of his truck. The grain weighed 5.2 tons (short). How many pounds did each bushel of wheat weigh?

11. Mass Conversions

12. Mass Conversions

13. Gabi weighs 116 lb. What is her mass to the nearest kilogram?

14. Apples cost $0.79 per pound. What is their cost per kilogram? Round your answer to the nearest cent.

15. How much does 1 gal of water weigh in pounds if 1 L of water has a mass of 1 kg? Round your answer to the nearest pound.

16. Connie is planning to lay a concrete driveway 60 ft long, 15 ft wide, and 4 in thick. If 1 yd3 of concrete weighs 4000 lb, how many tons of concrete are needed for the driveway? Round your answer to 1 decimal place.