eqX = m x''[t]==-k x'[t]

eqZ=m z''[t]==-m g -k z'[t]

sol=DSolve[{eqX,eqZ,x[0]==0,z[0]==0,z'[0]==V0 Sin[α],x'[0]==V0 Cos[α]},{x,z},t]//First

Z = z[t]/.sol

Z0=Limit[Z/.k->κ m,κ->0]

X=x[t]/.sol

X0=Limit[X/.k->κ m,κ->0]

T=t/.Solve[Z==0,t]//Last

T0=t/.Solve[Z0==0,t]//Last

zasiegInf=Limit[X,t->Infinity,Assumptions->m>0&&k>0]

zasiegTrue =X/.t->T//FullSimplify

zasieg0=X0/.t->T0//Simplify

m=Quantity[100,"Kilograms"]

(* dens=ElementData["Iron","Density"]*)

dens=ElementData["Tungsten","Density"]

dens//FullForm

R=(m/dens/Pi*3/4)^(1/3)

g=Quantity[9.81,"Meters"/"Seconds"^2]

A=4Pi R^2

ρ=Quantity[1,"Kilograms"/"Meters"^3]

Cd=1

V0=Quantity[200 ,"Meters"/"Seconds"]

k=1/2 ρ Cd A V0

α=Pi/4

T

T0

zasiegInf

zasiegTrue

zasieg0

zasiegTrue/zasiegInf

1-%

zasiegInf>zasiegTrue

ParametricPlot[{Evaluate@{X,Z},Evaluate@{X0,Z0}},{Quantity[t,"Seconds"],Quantity[0,"Seconds"],T},PlotRange->All]