Your physics professor is foolishly standing out in a field during a thunderstorm and measures two bolts of lightning to hit two trees at opposite ends of the field at exactly the same time. you, being considerably less foolish, are driving by in a car on a road right next to the field at a speed v when the lightning bolts strike the trees, one of which is in front of the car, the other of which is behind it. you happen to line up with the professor right when he observes the lightning bolts strike the trees. as measured by you in the car, a. the lightening bolts appear to hit at dofferent times, but once you factor in your speed in the car, you will agree that the bolts hit the trees at the same time. b. the lightening bolts do not hit both trees. c. the lightning bolts hit the trees at the same time. d. the lightening bolts do not hit the trees at the same time.

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).

prolly a beacuse the momentuem the car has increases while going down hill