Physics I can understand but how else has it been useful?
Industrial Automation:
A simple example is setting up a program in an industrial computer called a PLC. The PLC can measure the weight of the liquid in a completely sealed tank that is shaped like a can and is laying on its side. Like the ocean the pressure of the liquid increases from teh top to the bottom of the liquid. A device is installed that measures the pressure at the top of the tank which may be higher than the atmosphere and then takes a read at the bottom of the tank and figures the difference. Based on the density of the liquid it can determine the height of the liquid based on this difference of pressure using a calcluation. Since the tank is not round knowing the hieght does not tell you how much volume of the liquid you have. You have to then calculate what part of the can is filled with liquid and then determine the volume. The volumeis then sent to a display in a controll room with an alarm that goes off if it gets too low or high and the operators will have a truck fill the tank when it gets low.
Field of Measurement:
Natural gas for large volume customers can be measured using a plate taht restricts the flow of the gas and causes a difference of pressure before and after the restriction. Reads of this pressure can be taken to determine the flowrate. As the flow increases the restriction causes a greater drop of pressure after the restricting plate and the computer with the proper calucation can then determine the actual flow.
P/T = V The volume of gas is affected by temperature and pressure. All gas has to be measured at atmospheric pressure and 60 deg F. Since outside conditions and customer requirements for gas pressure do not allow for this we have to calculate what the volume of 600psi 35 deg F gas would have been had it been atmospheric pressure at 60 deg F. A device where the gas enters the pipe can measure how much actual heat 'btu' the gas can produce based on standard conditions. We charge the customers for the actual heat the gas can ideally produce and not the actual volume of gas we give them in case the gas contains impurities. So to calculate that you get a factor from this device that measures the heat of a standard cubic foot of gas and multiply that factor into the standard volume estimated based on non standard condiations to get a number that we use to charge the customer for the heat we provided them.
Speed control:
PID Proportional Integral and derivative, This is the calculation to determine the speed and the rate of change of speed to obtain a setpoint. An engine the size of a truck, not the engine in the truck, hooked up to a compressor that is the size of another truck compresses gas for a town. The engine has to keep a certain pressure as to not blow the pipe open or cause damage down stream or lose refineries due to under pressure conditions. PID controls the rate at which the compressor can ramp up and slow down in order to maintain the correct pressures. If it is off the compressor will not catch the pressure in time and it could blow safety devices that are set to keep the town safe and possibly cause an emergency shutdown. Or it could cut the supply to the refineries and cost millions of dollars in lost goods do to their own shutdown and issues caused by our inability to keep them supplied with gas.
GAMES:
I like to figure them out more than play them
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I build excell sheets like for D3 that calculates the leech, amor and damage blocked by armor etc..
I create a chart that can determine based on how much armor how much damage I would be able to block and how much damage I can take in a single hit before dying. This chart gives me an idea of a balanced and efficient build would be considering life, armor, leech, damage etc...
I also made a chart for POE that can estimate mana costs and the various methods of getting more mana regen in order to maintain certain skills. Once I know how much mana I need i can get just the right amount in my stats so I don't have to overdo it. To make the chart I had to use substitution so I can solve for different variables and determine how the affect eachtoebr and how they best work together.
Programming:
I was replicating a communication protocol between a device and my computer. I wanted to build my own software to control the device. The commuication had an error check code called a CRC which is an algorithm that can determine if there were any errors in transmission. I could not be certain of the divisor used. CRC is basically taking the binary representation fo the string and dividing it through the string and then recording the remainder. This remainder is then attached to the communication packet during transfer. The other computer then uses the known divisor against the string and sees if it gets the same remainder. IF the string was sent over the commuication lines intact both computers would have the same remainder. The recieving computer then accepts the communication packet as valid. if invalid it requests the packet again. Without the proper divisor I could not send the right error code and none of the commands would be accepted so I built a program that tested a number of divisors against a known string to receive a known remainder/error code. Basically hack the CRC algorithm. The program took 4 core processors and ran a month trying every number and it had barely gotten through a small peice of it and had not given me any good results. I stopped the program and set it up with commonly used divisors and had it test just those and got a valid divisor within a day.
Anyways I managed to replicate the protocol and have built a program that can control and configure the device.
But these are my more fun experiences. I did not includ the everyday tips calculations, taxes, making sure the right number of people are on the bus, or counting how many times someone can irritate me in a day.