Question

A runner burns 3.51×103kJ during a five-mile run. How many nutritional Calories did the runner burn?

Answer 1

Answer:

The runner burnt 8.39×10^5 nutritional Calories

Explanation:

1 Calorie = 4.184J

The runner burns 3.5×10^3kJ (3.5×10^6J) = 3.5×10^6/4.184 Calories = 8.39×10^5 nutritional Calories

Answer 2

Answer: The runner burnt 14.625 cal.

Explanation: KiloJoule and Calories are two unit of energy.

To convert kJ in cal:

1kJ = 0.24Kcal

3.51.10³ kJ = x

x = $\frac{3.51.10^{3} }{0.24}$

x = 14.625.10³ Kcal

However, it is asked for calories, not kilocalories. So, to find that it is only needed to divide the number by 1000 or multiply by $10^{-3}$:

14.625.10³.$10^{-3}$ = 14.625 cal

The runner burn 14.625 nutritional calories.