# Is the system linear if there is an independant gravity term

by silentwf
Tags: gravity, independant, linear, term
 P: 37 Okay, um then I should make it something like this: if my system is equation is something like: $f - mg - u = 0$ where f is the input and u is a disturbance (both are functions of time). having a scalar multiple of my force would not increase the system's response in a linear way. does this mean that this system is not linear? $f(a*t) - mg - u(t) = 0$