Question

directions: neatly answer the homework questions in your composition notebook.
energy unit conversion & data analysis homework packet
name: ___________________ date: ___________________

part 1: u.s. customary unit conversions
convert the following energy amounts. show all work.

1. convert 450 calories to kilocalories. (hint: 1 kilocalorie = 1000 calories)
2. convert 1200 btus (british thermal units) to calories. (hint: 1 btu ≈ 252 calories)
3. convert 1 horsepower-hour to btus. (hint: 1 horsepower-hour ≈ 2,545 btus)

part 2: metric energy conversions
convert using 1 calorie = 4.184 joules and 1 kilojoule = 1000 joules.

1. convert 250 calories to joules.
2. convert 12,000 joules to kilojoules.
3. convert 3,000 kilojoules to calories.

part 3: energy data analysis & graphing
a group of students measured energy output from different foods and recorded the energy in kilojoules (kj):

food item	energy (kj)
banana	440
slice of bread	280
cheese	1,050
chicken	2,100
cookie	850
orange	300

1. convert the energy for each food item into calories. (use 1 kj = 239 calories)
2. create a frequency table for the energy ranges: 0–500 kj, 501–1,000 kj, 1,001–1,500 kj, 1,501–2,500 kj.
3. construct a frequency bar graph using your table. (label axes clearly: “energy range (kj)” on x-axis, “number of food items” on y-axis.)
4. interpret your graph: which energy range is most common? what does this suggest about typical foods?

Explanation:

Part 1: U.S. Customary Unit Conversions

1. Convert 450 calories to kilocalories

Step1: Recall the conversion factor

1 kilocalorie = 1000 calories, so to convert calories to kilocalories, divide by 1000.

Step2: Perform the calculation

$\frac{450 \text{ calories}}{1000 \text{ calories/kilocalorie}} = 0.45 \text{ kilocalories}$

Step1: Recall the conversion factor

1 BTU = 252 calories, so multiply BTUs by 252.

Step2: Perform the calculation

$1200 \text{ BTUs} \times 252 \text{ calories/BTU} = 302400 \text{ calories}$

Step1: Recall the conversion factor

1 horsepower - hour = 2545 BTUs.

Step2: Perform the calculation

$1 \text{ horsepower - hour} \times 2545 \text{ BTUs/horsepower - hour} = 2545 \text{ BTUs}$

Answer:

0.45 kilocalories

2. Convert 1200 BTUs to calories