A 68-kg person walks at 5 km per hour for 1 hour a day for 1 year. Estimate the extra number of

step 1 Question number 87 in the table it is given that when a person walks moderately at three miles p

A 68-kg person walks at 5 km per hour for 1 hour a day for 1...

A 68-kg person walks at $5 \mathrm{km}$ per hour for 1 hour a day for 1 year. Estimate the extra number of kilocalorics of energy used because of the wallking.
(a) $40,000 \mathrm{kcal}$
(b) $47,000 \mathrm{kcal}$
(c) $88,000 \mathrm{kcal}$
(d) $150,000 \mathrm{kcal}$

Key Concepts

Estimation Techniques in Physics

Estimation techniques involve making approximate calculations to determine quantities when exact data is not available. This includes using order-of-magnitude reasoning, simplifying assumptions like average values for body mass, walking speed, and metabolic efficiency. Such techniques are crucial in solving real-world problems by providing a reasonable approximation of energy expenditure without intricate models.

Conversion Factors in Energy Calculations

Conversion factors are central to connecting the physics of mechanical work with the nutritional units used in metabolism. For example, it is essential to know that one kilocalorie is equivalent to approximately 4184 joules. This allows one to translate between the energy expended in joules (a standard SI unit) and kilocalories (commonly used in dietary energy calculations).

Mechanical Work and Power

Mechanical work is defined as the product of force and displacement, and power is the rate at which work is done. In physical activities, understanding how the body converts energy into movement through doing work is crucial. Estimations of energy expenditure often involve calculating the total work over a time period, then relating it to power output, which helps in determining the energy cost of the exercise.

Energy Expenditure in Physical Activity

This concept deals with how the human body uses energy to perform physical tasks. It involves understanding that during activities like walking, metabolic processes oxidize food, converting chemical energy into mechanical work. In energy calculations, one must account for the efficient and inefficient aspects of biological energy use, differentiating between basal metabolic rates and additional energy costs of activity.

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