Physics
Distance vs displacement: how can displacement be zero?
Displacement is zero whenever you finish exactly where you started. Distance is the length of the path you actually travel, so it only has...
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Maths
How to write equations from word problems in 4 steps
To write an equation from a word problem, use four steps. Name the unknown with a letter and its units ("let d be the distance in mil...
Builds
ESP32 LED blink: code, circuit and the resistor you need
To blink an LED with an ESP32, wire GPIO 23 to a 220 Ω resistor, the resistor to the LED's long leg, and the short leg to GND. Then up...
Code
How do computers add numbers? Binary and logic gates
Computers add numbers in binary, with circuits built from logic gates. Every binary digit is a switch that is on (1) or off (0). An XOR g...