A 47 kg person walking 5.4 km/hr requires 838 kJ of energy per hour.

Question

A 47 kg person walking 5.4 km/hr requires 838 kJ of energy per hour. How much further does he have to walk to consume the additional energy contained in 300 g of ground beef relative to 300 g of broiled chicken? The energy content of ground beef is 16 kJ/g, while that of chicken is 6.0 kJ/g.

I'm trying to cancel out the units in order to get a final answer in km, but so far all I have is 838 kj / 5.4 km * 1 / 16 kj. Not sure what to do next, thank you for any help!

Answer 1

Start with what you know extensively (property that depends on amount of material)

300 grams of chicken (6 kJ/g C)(5.4 km/839kJ) = km

Do the same for beef and compare. Notice I made a new conversion factor by dividing km/hr by kJ/hr to connect km and kJ.