An apple falls from a tree. it hits the ground at a speed of about 8 m/s . what is the approximate height of the tree?

The motion of the apple is a free fall motion, so it is a uniformly accelerated motion. Therefore, we can use the following equation:

where

v=8 m/s is the speed of the apple when it hits the ground

u=0 is the initial speed of the apple

is the free-fall acceleration

h is the height from which the apple has fallen

Substituting data and rearranging the equation, we can find the height of the tree, h:

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).

54 degrees incident angle = reflected angle

angle is from normal turned to line of ray