Normally the rate at which you expend energy

during a brisk walk is 3.6 Calories per minute.
(A Calorie is the common unit of food energy,
equal to 4184.1 J.)
How long do you have to walk to produce
the same amount of energy as a 100 W lightbulb that is lit for 8.4 hours?
Answer in units of h

see other post

To find out how long you have to walk to produce the same amount of energy as a 100 W lightbulb that is lit for 8.4 hours, we need to calculate the total energy expended during the walk and compare it to the energy consumed by the lightbulb.

Step 1: Calculate the energy expended during the walk:
The rate at which you expend energy during a brisk walk is given as 3.6 Calories (food energy) per minute. To convert this to joules, we'll use the conversion factor that 1 Calorie is equal to 4184.1 joules.

Energy expended during the walk = rate of energy expenditure × time
Energy expended during the walk = (3.6 Calories/minute) × (4184.1 J/1 Calorie) × (walking time in minutes)

Step 2: Calculate the total energy consumed by the lightbulb:
The power consumption of the lightbulb is given as 100 watts (W) and it is lit for 8.4 hours.

Energy consumed by the lightbulb = power × time
Energy consumed by the lightbulb = (100 W) × (8.4 hours) × (3600 seconds/1 hour)

Step 3: Compare the energy expended during the walk to the energy consumed by the lightbulb:

Set Energy expended during the walk = Energy consumed by the lightbulb and solve for walking time.

(3.6 Calories/minute) × (4184.1 J/1 Calorie) × (walking time in minutes) = (100 W) × (8.4 hours) × (3600 seconds/1 hour)

Now, simplify and solve the equation for walking time:

walking time in minutes = ((100 W) × (8.4 hours) × (3600 seconds/1 hour)) / ((3.6 Calories/minute) × (4184.1 J/1 Calorie))

Since the question asks for the answer in hours, we need to convert the walking time from minutes to hours by dividing the walking time in minutes by 60.

walking time in hours = walking time in minutes / 60

Now, you can plug in the values and calculate the answer.