A sleeping 68 kg man has a metabolic power of 71 W. How many Calories does he burn during an 8.0 hour sleep?

A 170 pound man wants to design a workout (on a treadmill) that will expend 300 kcal.  He wants to walk 45 min. at a speed of 3.5 mph.  What elevation does he need to set the treadmill to complete this workout?

The motor that drives a refrigerator produces 151 W of useful power. The hot and cold temperatures of the heat reservoirs are 20.0°C and -5.00°C. What is the maximum possible amount of ice it can produce in 2.00 h from water that is initially at 8.00°C? Latent heat of fusion of ice is 333700 J/kg and specific heat capacity of water is 4186 J/(kg-K). kg

If I add 11664 J of energy to an ideal gas inside a balloon, causing the internal energy to increase by 7278 J, how much work is done on the environment by the gas as the balloon expands?

A 46-kg woman cheats on her diet and eats a 555-Calorie (555 kcal) jelly doughnut for breakfast. (a) How many joules of energy are the equivalent of one jelly doughnut? (b) How many stairs must the woman climb to perform an amount of mechanical work equivalent to the food energy in one jelly doughnut? Assume the height of a single stair is 15 cm. stairs (c) If the human body is only 20% efficient in converting chemical energy to mechanical energy, how many stairs must the woman climb to work off her breakfast? stairs Need Help? Read It

A weightlifter curls a 26 kg bar, raising it each time a distance of 0.65 m . How many times must he repeat this exercise to burn off the energy in one slice of pizza?  Assume 25% efficiency. Energy content of one slice of pizza is 1260  kJ

A 46-kg woman eats a 522 Calorie (522 kcal) jelly doughnut for breakfast. (a) How many joules of energy are the equivalent of one jelly doughnut? 2.19 Your response differs significantly from the correct answer. Rework your solution from the beginning and check each step carefully. J (b) How many steps must the woman climb on a very tall stairway to change the gravitational potential energy of the woman-Earth system by a value equivalent to the food energy in one jelly doughnut? Assume the height of a single stair is 15 cm. 3.22 X Your response differs significantly from the correct answer. Rework your solution from the beginning and check each step carefully. stairs (c) If the human body is only 26% efficient in converting chemical potential energy to mechanical energy, how many steps must the woman climb to work off her breakfast? 8.4 X Your response is off by a multiple of ten. stairs

A typical coal-fired power plant burns 340 metric tons of coal every hour to generate 2.5 × 106 MJ of energy. One metric ton has a mass of 1000 kg and a metric ton of coal has a volume of 1.5 m^3. The heat of combustion is 28 MJ/kg. What is the power plant’s efficiency?

A student evaluates a weight loss program by calculating the number of times she would need to climb a 10.0 m high flight of steps in order to lose one pound (0.45 kg) of fat. Metabolizing 1.00 kg of fat can release 3.77 x 10'J of chemical energy and the body can convert about 21.2% of this into mechanical energy (the rest goes into internal energy.) HINT (a) How much mechanical energy (in J) can the body produce from 0.450 kg of fat? (b) How many trips up the flight of steps are required for the 52.0 kg student to lose 0.450 kg of fat? Ignore the relatively small amount of energy required to return down the stairs. trips Need Help? Read It Watch It

Explain with the formulas please