When an object with a negative charge is moved from point A to point B through an external electrical field, it gains electrical potential energy. When an object with positive charge is moved from point A to point B though the same field, it loses electrical potential energy. Which of the following statements is true? Select all that apply.

A. Because the positive and negative charges cancel out, the potential difference between A and B is zero (that is, VB = VA).
B. The positively charged object moves through a negative potential difference between A and B (that is, VB - VA < 0).
C. The negatively charged object moves through a negative potential difference between A and B (that is, VB - VA < 0).
D. The negatively charged object moves through a positive potential difference between A and B (that is, VB - VA > 0).
E. The positively charged object moves through a positive potential difference from A and B (that is, VB - VA > 0).

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

What is the efficiency of an engine that does 80 j of work and exhausts 320 j of heat while taking in 400 j of heat ? a. 10% b. 20% c. 80% d. 25%

What do the atoms of elements in the same group have in common? a. they have the same atomic numbers. b. they have the same average atomic masses. c. they have the same number of electron shells. d. they have the same number of electrons in their outermost shells.