A hot water heater in a residential home runs for an average of 2.2 hours per day with a heat energy input of 3.8 kW.  What would be the annual cost for hot water in this home using a gas hot water heater if the cost of natural gas is $0.35/m3?  The gas water heater can get 21 MJ of energy from 1 m3 of natural gas.

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

If I add 12,183 J of energy to an ideal gas inside a balloon causing the internal energy to increase by 5185 J, how much work is done on the environment by the gas as the balloon expands?

For a total PV module of 25m2, what would be the PV power for each if conversion efficiency is 15% on days when an angle of a south-facing collector in [city] be tipped up to have it normal to the Sun's rays at solar noon?

Find for the Cross Product of the following pairs of vectors 1. A=4i-5j +8k, B = -2i+3j+3k 2. C = -6i+4j+7k, D=4i-j+5k 3. E= -i-5j + 2k, F = 8i+2j-6k

An electrical power station uses 1.33 1014 J of heat input with an efficiency of 34.7%. (a) How much work is done? (b) How much waste heat is produced by the station?   (c) What is the ratio of waste heat to work output?

The metabolic power for typing is 150 W for Lili, not a lot as you know probably. How long does it take to burn off the energy in a slice of apple pie, which energy content is 1680 kJ (400 food calorie), in minutes?  (Try to stay active, working/studying in front of a computer is not the best exercise you can do for your body.) Your answer needs to have 3 significant figures, including the negative sign in your answer if needed. Do not include the positive sign if the answer is positive. No unit is needed in your answer, it is already given in the question statement.

If mass of air in a house is 278.6376kg. And the specific heat of air is 1.0kj/kgK. How much heat energy is needed to heat air by 10K?   Use Q=mc∆T

A 1000W electric kettle contains 1200g of water at 25*C. In how many minutes after the power is switched on is 200 g left in the kettle?

An aluminum rod is 30cm long at 33°C and has a mass of 330g. If 13,000 J of energy is added to the rod by heat, what is the change in length of the rod? Do not use scientific notation and enter your answer in m.