Physics, 31.03.2020 00:17 haydenamrhein1693
A camera lens used for taking close-up photographs has a focal length of 23.0 mm. The farthest it can be placed from the film is 34.0 mm. (a) What is the closest object (in mm) that can be photographed
Answers: 2
Physics, 22.06.2019 05:00
Which car has the most kinetic energy? a. a car of mass 1000 kg with a speed of 3 m/s b. a car of mass 2000 kg with speed 7 m/s c. a car of mass 1000 kg with speed 7 m/s d. a car of mass 2000 kg with speed 3 m/s
Answers: 1
Physics, 22.06.2019 08:00
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?
Answers: 2
Physics, 22.06.2019 11:50
The mass of the sun is 1.99×1030kg and its distance to the earth is 1.50×1011m. what is the gravitational force of the sun on the earth?
Answers: 3
A camera lens used for taking close-up photographs has a focal length of 23.0 mm. The farthest it ca...
Mathematics, 31.07.2020 08:01
Mathematics, 31.07.2020 08:01
English, 31.07.2020 08:01
Mathematics, 31.07.2020 08:01
French, 31.07.2020 08:01
Mathematics, 31.07.2020 08:01
Mathematics, 31.07.2020 08:01
Mathematics, 31.07.2020 08:01
Mathematics, 31.07.2020 08:01