Electron (-) has a charge of 1.6 x 10-19 C. Proton (+) has a charge of 1.6 x 10-19 C. In a hydrogen atom the distance between a proton and an electron is
5.3 x 10-12 meter.
(A) Calculate the force acting between the proton and the electron. Show your work. Remember to include a correct force unit in your final answer.

(B) Why does it generally require energy (ionization energy) to remove an electron from an electron cloud? Hint: think of charges.

(C) To lift a 2lb dumbell off the floor to a height of your thigh would require about one Newton of force (1N). How many dumbells at once would you have to pick off a floor to your the height of your tight to show the magnitude of force acting between a proton and an electron?

2-lb dumbbell

Aheat engine running backward is called a refrigerator if its purpose is to extract heat from a cold reservoir. the same engine running backward is called a heat pump if its purpose is to exhaust warm air into the hot reservoir. heat pumps are widely used for home heating. you can think of a heat pump as a refrigerator that is cooling the already cold outdoors and, with its exhaust heat qh, warming the indoors. perhaps this seems a little silly, but consider the following. electricity can be directly used to heat a home by passing an electric current through a heating coil. this is a direct, 100% conversion of work to heat. that is, 19.0 \rm kw of electric power (generated by doing work at the rate 19.0 kj/s at the power plant) produces heat energy inside the home at a rate of 19.0 kj/s. suppose that the neighbor's home has a heat pump with a coefficient of performance of 4.00, a realistic value. note: with a refrigerator, "what you get" is heat removed. but with a heat pump, "what you get" is heat delivered. so the coefficient of performance of a heat pump is k=qh/win. an average price for electricity is about 40 mj per dollar. a furnace or heat pump will run typically 200 hours per month during the winter. what does one month's heating cost in the home with a 16.0 kw electric heater? what does one month's heating cost in the home of a neighbor who uses a heat pump to provide the same amount of heating?