When a person eats a sandwich before a hike, the energy transformation that occurs can be described as the conversion of chemical potential energy stored in the food into mechanical energy used by the person's body.
The sandwich contains nutrients such as carbohydrates, fats, and proteins. During digestion, these macronutrients are broken down into smaller molecules and absorbed into the bloodstream. Through cellular respiration, the body's cells convert these molecules into adenosine triphosphate (ATP), which is a form of chemical energy.
During the hike, the ATP molecules are broken down by the cells, releasing the stored chemical energy. This energy is then utilized by the body's muscles to perform mechanical work, allowing the person to walk, climb, and engage in physical activities.
In summary, the energy transformation involves the conversion of chemical potential energy in the sandwich into ATP, and then the conversion of ATP into mechanical energy used by the person's body during the hike.