A 20 kg block rests on a rough horizontal table. A rope is attached to the block and is pulled with a force of 80 N to the left. As a result, the block accelerates at 2.5 m/s2. What is the coefficient of kinetic friction between the block and the table?

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

One form of energy can be another type of energy. a. created to form b. transformed into c. destroyed and then created to form

Which is not an example of how an object gains elastic potential energy by stretching? a. jumping on a pogo stick b. pulling on a rubber band c. jumping on a trampoline