Hello all, Im only a student, taking physics in college in september, However I have read up on the level of physics I will be studying. One thing that I couldn't get my head round, Why when an object aproaches c does its mass increase? Am I right in saying this also makes it impossible from the object to reach c? Also why does this cancel out f = ma? Sorry if this seems like a stupid question, but it just sparked an interest in my mind and I couldn't find an explanation that actually fully explained it to me. Thanks all.