A cue ball of mass m1 = 0.395 kg is shot at another billiard ball, with mass m2 = 0.54 kg, which is at rest. The cue ball has an initial speed of v = 7.5 m/s in the positive direction. Assume that the collision is elastic and exactly head-on. a) Write an expression for the horizontal component of the billiard balls velocity, v2f after the collision, in terms of the other variables of the problem. b) What is this velocity, in meter per second? c) Write an expression for the horizontal component pf the cueball's velocity, v1f after the collision. d) What is the horizontal component of the cue ball's velocity, in meter per second?

most voltage drop calculators want the distance between the source and destination. then internally, they double it so both the source and return wires are calculated. but you need to know which distance the calculator uses so you're not half of what you should be or double what you should be.

most circuit breakers will not take a #6 directly, so the electrician will have to splice on a smaller pigtail. you also have to upsize the grounding wire when you upsized the ungrounded (hot) wire (see note in 250.122). this will preclude using most cable assemblies, as a cable with #6 copper will most likely only have a #10 grounding conductor. you need a #6 grounding conductor if the circuit is 20a. a #8 cable is no better, as it will have a #10 grounding conductor too. but most 20a breakers will take a #8 directly.

in your related post, you didn't say what type of load this is. if it is a light or heater, voltage drop won't be a big issue. if this is a motor, the current needs are huge at startup and the voltage drop can pose a problem. if this is a motor, knowing if the motor is under much load during startup will answer the voltage drop effect (a saw is easier to start than a compressor).

beta is electron from nucleus

something from nucleus has changed, but charge must be same for cons of charge