[Moderator's note: thread title edited for greater clarity] If you apply a constant force to an object, will it eventually begin to asymptote towards a specific velocity? My reasoning is that with special relativity we can re-write f = ma as F =(m0/(1 - v2/c2)1/2)a. Because of this equation, as the mass is accelerated due to the force, the object's mass increases. This makes the acceleration due to the force applied smaller. Am i correct in my thinking?