8. a 740 kg car traveling 19 m/s comes to a complete stop in 2.0 s. what is the force exerted on the car during this stop?

Solar cell a produces 100 joules of energy, when a light source is shown on it for 3 minutes. solar cell b produces 200 joules of energy when the same light source is shown on it for 5 minutes. which solar cell works better? a) solar cell b, because it produces more energy. b) solar cell b, because it generates more power. c) solar cell a, because it produces energy quicker. d) solar cell a, because it generates a greater wattage. eliminate

The softest and hardest minerals are: softest hardest

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?