The correct answer is B. Electrons flow because of electrical attraction and repulsion.
Explanation:
Let
= distance traveled while accelerating
= distance traveled while decelerating
The distance traveled while accelerating is given by
![x_1 = v_0t + \frac{1}{2}at^2 = \frac{1}{2}at^2](https://tex.z-dn.net/?f=x_1%20%3D%20v_0t%20%2B%20%5Cfrac%7B1%7D%7B2%7Dat%5E2%20%3D%20%5Cfrac%7B1%7D%7B2%7Dat%5E2)
![\:\:\:\:\:= \frac{1}{2}(2.5\:\text{m/s}^2)(30\:\text{s})^2](https://tex.z-dn.net/?f=%5C%3A%5C%3A%5C%3A%5C%3A%5C%3A%3D%20%5Cfrac%7B1%7D%7B2%7D%282.5%5C%3A%5Ctext%7Bm%2Fs%7D%5E2%29%2830%5C%3A%5Ctext%7Bs%7D%29%5E2)
![\:\:\:\:\:= 1125\:\text{m}](https://tex.z-dn.net/?f=%5C%3A%5C%3A%5C%3A%5C%3A%5C%3A%3D%201125%5C%3A%5Ctext%7Bm%7D)
We need the velocity of the rocket after 30 seconds and we can calculate it as follows:
![v = at = (2.5\:\text{m/s}^2)(30\:\text{s}) = 75\:\text{m/s}](https://tex.z-dn.net/?f=v%20%3D%20at%20%3D%20%282.5%5C%3A%5Ctext%7Bm%2Fs%7D%5E2%29%2830%5C%3A%5Ctext%7Bs%7D%29%20%3D%2075%5C%3A%5Ctext%7Bm%2Fs%7D)
This will be the initial velocity when start calculating for the distance it traveled while decelerating.
![v^2 = v_0^2 + 2ax_2](https://tex.z-dn.net/?f=v%5E2%20%3D%20v_0%5E2%20%2B%202ax_2)
![0 = (75\:\text{m/s})^2 + 2(-0.65\:\text{m/s}^2)x_2](https://tex.z-dn.net/?f=0%20%3D%20%2875%5C%3A%5Ctext%7Bm%2Fs%7D%29%5E2%20%2B%202%28-0.65%5C%3A%5Ctext%7Bm%2Fs%7D%5E2%29x_2)
Solving for
we get
![x_2 = \dfrac{(75\:\text{m/s})^2}{2(0.65\:\text{m/s}^2)}](https://tex.z-dn.net/?f=x_2%20%3D%20%5Cdfrac%7B%2875%5C%3A%5Ctext%7Bm%2Fs%7D%29%5E2%7D%7B2%280.65%5C%3A%5Ctext%7Bm%2Fs%7D%5E2%29%7D)
![\:\:\:\:\:= 4327\:\text{m}](https://tex.z-dn.net/?f=%5C%3A%5C%3A%5C%3A%5C%3A%5C%3A%3D%204327%5C%3A%5Ctext%7Bm%7D)
Therefore, the total distance x is
![x = x_1 + x_2 = 1125\:\text{m} + 4327\:\text{m}](https://tex.z-dn.net/?f=x%20%3D%20x_1%20%2B%20x_2%20%3D%201125%5C%3A%5Ctext%7Bm%7D%20%2B%204327%5C%3A%5Ctext%7Bm%7D)
![\:\:\:\:= 5452\:\text{m}](https://tex.z-dn.net/?f=%5C%3A%5C%3A%5C%3A%5C%3A%3D%205452%5C%3A%5Ctext%7Bm%7D)
I believe the answer would be A. because a magnet has both a south and a north pole, and electrical charges are formed by positive and negative forces. Hope I helped!