Read the excerpt from The Boy Who Harnessed the Wind by William Kamkwamba.

I could get money by working ganyu. At the time, guys were making one hundred kwacha unloading trucks at CHiPiKU store, so I headed there. If I worked a whole week, I could have enough. I waited outside the store all morning and into the afternoon. The sun was dreadful, and I had no water. Finally the owner walked outside and saw me.

"Why are you standing here?" he said.

"Waiting for trucks."

"Trucks come every day," he said. "Except Monday."

It was Monday.

That night at home, I hit upon another idea. The bicycle dynamo was the ideal generator for the bigger windmill I wanted to create, and at some point I'd have to work for the money to buy it. But for this experimental model, I could get by with using a much smaller generator, and I knew just where to find that.

Which character trait do the details in the excerpt reveal about Kamkwamba?

greed
kindness
persistence
laziness

Fft review: linspace, fs, fftshift, nfft 1. generate one second of a cosine of w,-10hz sampled at f, = 100hz and assign it to x. define a tt as your time axis 2. take 64 points fft. 3. as you remember, the dft (which the fft implements) computes n samples of s2t where k-0,1,2, n -1. plot the magnitude of this 64-points fft at range 0 to 63, what do you think of this graph? 4â·to get the x-axis into a hz-frequency form, plot this 64-points fft between-50 to 50 (the 100hz sampling rate) and have n-points between them. 5. according to your figure, what frequency is this cosine wave at? 6. remember that the fft is evaluating from 0 to 2ď€. we are used to viewing graphs from-ď€ to ď€. therefore, you need to shift your graph. 7. now according to your shifted graph. what frequency is this at? 8. note that the spikes have long drop-offs? try a 1024-point dft. note that the peak is closer to 10 and the drop-off is quicker. although, now sidelobes are an issue

15. one purpose of the tread pattern on a tire is to a reduce tire wear. b. reduce traction c. allow water to flow away from the tire. d. look impressive.

What is the increase in density of a medium due to wave travel?