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# Terminal velocity (physics) Standing steam iron amazonfree detective games on steam TERMINAL VELOCITY™: BOOSTED EDITION review lets determine the equation for the terminal velocity of a following mass so you can treat this as a for instance a skydiver jumping out of an airplane accelerates downward due to gravity and then the year the wind on him will push him up and will balance the force of gravity so that he reaches a constant velocity okay so here is the falling mass and gravity force is in in down direction and then if the velocity if the mass is falling so the velocity is down then the air resistance force will be up so we assume that there is no air resistance when the velocity is zero and then with increasing velocity theres an increasing air resistance so we want to model these forces so we write down Newtons equation so mass times the acceleration which we write as DV DT is equal to the gravitational force which is minus M G G is the usual 9.8 meters per second squared to find this positive so the forces in the negative direction and then a force due to air resistance which is proportional to the velocity so heres the proportionality constant is K times the velocity K is a constant which will take to be a positive proportionality constant and then theres a sign here a plus or minus sign so in with this axis drawn up and if the velocity is downward so V is negative here V is negative here then the force is supposed to be positive direction so a negative V to make this term positive should be a minus sign it also works if V is positive if the ball was moving up then the force would be in the opposite direction down sophie was positive the force would be negative so theres still a minus sign so in general this is the correct equation provided that our axis here is pointing upward okay the chiken equation changes if we change the direction of the axis but the physics is the same okay and then we can solve this equation with an initial condition so well assume that the masses perhaps a skydiver so at t equals zero the velocity of the mass we take to be zero so that would be the vertical velocity of the mass okay so this is both a separable equation in a linear equation we can solve that either by separating variables or using the equation four for the solution of the linear equation if we separate variables we can write DV DT equals minus G minus K over M V or maybe a minus plus right and then separate the variables so DV over G Plus K over m V equals minus DT integrate from T equals zero to T from the initial velocity of zero to a velocity of V this left hit right hand side is simply minus T right the left hand side looks like a lock we have to to change variables we can let u equals G plus K over m V so D u equals K over m DV right so then we need a multiplied by K over m on the inside to convert K over m DV to D U and then on the outside we need to multiply by M over K so we have M over K times the integral and then we have a K over m DV becomes a D U and G plus K over m v becomes a U and the limits when V equals 0 U is G and when V equals V U is a G Plus K over m v right thats the left-hand side so thats going to be both new the lower limit and the upper limit or positive so that becomes M over K log G plus K over m v divided by G and thats supposed to be equal to minus T so we multiply by K over m and take the exponential of both sides and then multiply by G so we end up with G plus K over m v equals some G times e to the minus K T over m right and then we subtract G and multiplied by M over K so we get V of T equals M over mg over K lets see subtract G multiplied by M over K and then we have an e to the minus KT over M minus 1 so I can pull out the minus sign and then we have a 1 minus e to the minus KT over m okay and thats the equation for the velocity so the terminal velocity is when T goes to infinity so the terminal velocity vt is a limit or maybe we should call it V infinity is the limit as T goes to infinity of V of T which will be the exponential goes to zero so its minus mg over K right which we could have gotten from the differential equation by setting simply setting DV DT equal to zero right so when DV DT equals zero then these is minus mg over K so thats the terminal velocity and our equations gave us the approach to terminal velocity as exponential so if we use V infinity then weve got V of T is equal to V infinity times 1 minus e to the minus KT over m okay its interesting to put in some numbers here for instance if we know that the terminal velocity of a skydiver is something like 200 kilometers per hour right and that the mass of the skydiver is say 100 kilograms so thats the person plus all of his equipment right then we can compute K and we find that K turns out to be sixty three thousand five hundred and four kilograms per hour right and we get V of T equals one-half the terminal velocity right at a time so we can solve this equation for T and when we do that we see that a skydiver will attain 100 kilometers per hour speed when T is about four seconds okay four seconds and then V of T equals 95% of the terminal velocity right and plugging that in we will find this is about 17 seconds okay so the skydiver will go from 0 to 100 km/h in about 4 seconds and then 100 km/h to 190 km/h in additional 13 seconds steam deck game prices Find and solve the differential equation for the terminal velocity of a mass falling under gravity opposed by air resistance.Join me on Coursera: Matrix Algebra for Engineers: Differential Equations for Engineers: Vector Calculus for Engineers: red dead online steam best multiplayer steam games free steamed beancurd baby bullet steamer manual wow steam deck