1 Cal = 1000 cal 1 cal = 4.184 joules 1 joule = .001 kJ
First, you need to convert the Calories into kJoules (2,171 Cal)(1000) = 2,171,000 cal (2,171,000 cal)(4.184) = 9,083,464 joules 9,083,464 joules(0.001) = 9,083.464 kJoules
Then, multiply the value by two to get your answer
In this case, given that 1 inch equals 2.54 cm and 1 lb equals 453.6 g we apply the following conversion factor in order to compute the required density in lb/in³: