Because you simply asked me how long it would take an object to reach 300,000 m/s if it was always accelerating at 9.8m/s/s. That's simple maths, as presumably you insist on the existence of some unknown way of overcoming the increase in mass, and presuming it is in a perfect vacuum.
Of course, this would be relativistic, i.e. timed by a an observer on the accelerating body, in this case, us.
Tell me how I'm wrong.
Do explain.