Hi all. New to physics forum and glad to be here. I have been referencing the site for a while now and have finally come up with a question i haven't been able to find on here. So I guess i thank all of you who are already on here for the help. Assumptions: -Imagine an infinitely large plate (just so the field lines are all going in the same direction) -This plate is super dense -The plate is fixed in space and cannot bend -It is arbitrarily far away (in a vacuum duh) -There is a ball of relatively small mass (or rest mass because this will change) Question: The ball is released and begins its long travel to the plate accelerating towards the plate. After a while it is really moving quickly. As it approaches the speed of light it gains mass (that is what I have always been told). But the force between the two should be growing proportional to the increased mass (that is using the general theory of gravity). As this force increases, the acceleration should stay the same. If that were true there shouldn't be anything stopping the particle from reaching the speed of light. Unless there is a force that (i don't know about) inhibits masses from reaching it.