Aball is dropped from rest at point o (height unknown). after falling for some time, it passes by a window of height 3 m and it does so in 0.49 s. the ball accelerates all the way down; let va be its speed as it passes the window’s top a and vb its speed as it passes the window’s bottom b. o a b 3 m bb b b b b b b b b b b x y how much did the ball speed up as it passed the window; i. e., calculate ∆vdown = vb −va ? the acceleration of gravity is 9.8 m/s 2 . answer in units of m/s. 017 (part 2 of 2) 10.0 points calculate the speed va at which the ball passes the window’s top. answer in units of m/s.

Write the function getkthdigit(n, k) that takes a possibly-negative int n and a non-negative int k, and returns the kth digit of n, starting from 0, counting from the right

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?

How many times did thomas edison mess up the light bulb