Problem: Since the early days of rail transport in the United States, Philadelphia has served as hub for several major rail companies, particularly the Pennsylvania Railroad and the Reading Railroad. The Pennsylvania Railroad first operated Broad Street Station, then 30th Street Station and Suburban Station, and the Reading Railroad operated out of Reading Terminal, now part of the Pennsylvania Convention Center. The two companies also operated competing commuter rail systems in the area, known collectively as the Regional Rail system. The two systems today, for the most part still intact but now connected, operate as a single system under the control of the SEPTA, the regional transit authority. Additionally, the PATCO Speedline subway system and NJ Transit's Atlantic City Line operate successor services to southern New Jersey.
Name 2 rail companies that use the city as a hub?
The answer is the following: Pennsylvania Railroad and the Reading Railroad

Problem: The current I(t) through any component in an electric circuit is defined as the rate of flow of a charge Q(t) passing through it, but actual charges—electrons—cannot pass through the dielectric layer of a capacitor. Rather, one electron accumulates on the negative plate for each one that leaves the positive plate, resulting in an electron depletion and consequent positive charge on one electrode that is equal and opposite to the accumulated negative charge on the other. Thus the charge on the electrodes is equal to the integral of the current as well as proportional to the voltage, as discussed above. As with any antiderivative, a constant of integration is added to represent the initial voltage V(t0). This is the integral form of the capacitor equation:
For each electron that departs the positive plate, how many electrons build up on the negative plate?
The answer is the following: one electron accumulates on the negative plate

Problem: Based on studies of these bronze inscriptions, it is clear that, from the Shang dynasty writing to that of the Western Zhou and early Eastern Zhou, the mainstream script evolved in a slow, unbroken fashion, until assuming the form that is now known as seal script in the late Eastern Zhou in the state of Qin, without any clear line of division. Meanwhile, other scripts had evolved, especially in the eastern and southern areas during the late Zhou dynasty, including regional forms, such as the gǔwén ("ancient forms") of the eastern Warring States preserved as variant forms in the Han dynasty character dictionary Shuowen Jiezi, as well as decorative forms such as bird and insect scripts.
What is guwen considered as?
The answer is the following: ancient forms

Problem: Karl Popper's rejection of Marxism during his teenage years left a profound mark on his thought. He had at one point joined a socialist association, and for a few months in 1919 considered himself a communist. During this time he became familiar with the Marxist view of economics, class-war, and history. Although he quickly became disillusioned with the views expounded by Marxism, his flirtation with the ideology led him to distance himself from those who believed that spilling blood for the sake of a revolution was necessary. He came to realise that when it came to sacrificing human lives, one was to think and act with extreme prudence.
For a time during which year did Popper consider himself a communist?
The answer is the following:
1919