A2,511 kg railroad car moving at 4.192 m/s to the east collides with a 8,199 kg railroad car moving at 3.781 m/s to the west. if the cars couple together, what is their velocity after the collision?

Along the line connecting the two charges, at what distance from the charge q1 is the total electric field from the two charges zero? express your answer in terms of some or all of the variables s, q1, q2 and k =14ï€ïµ0. if your answer is difficult to enter, consider simplifying it, as it can be made relatively simple with some work.

Achlorine atom has 17 protons and 18 neutrons. what is its mass number? what is its atomic number?

Exercise 2. find the wavelength of a photon emitted when an electron jumps from the n = 3 energy level down to the n = 2 energy level. where is this photon in the electromagnetic spectrum?