Question

The nutritional calorie (Calorie) is equivalent to 1 kcal. One pound of body fat is equivalent to about 4.1 x 103 Calories. If a runner expends 1850 kJ/h, how long (h) does she have to run to work off 7.56 lb of body fat? Enter your answer in decimal format with one decimal place.

Answer 1

Answer:

$t = 70.13 hours$

Explanation:

As we know that 1 lb fat can be used to expend 4.1 k Calorie of energy

so here we know that we have to use 7.56 lb of body fat

so here the total energy that is to be utilized is given as

$Q = (4.1 \times 10^3)(7.56)$

so we will have

$Q = 30996 Calorie$

now we know that runner expends the energy at rate of 1850 kJ/h

so we have

$E = 1850 \times 10^3 kJ/h$

so it is

$E = 0.44 \times 10^3 calorie/h$

now we know that time to burn this energy is given as

$t = \frac{Q}{E}$

$t = \frac{30996}{0.44 \times 10^3}$

$t = 70.13 hours$