So I dont really understand how to see if equations are linear or nonlinear so, is y= 6x linear or not? As well as 6x + 4y = 8, y = 6x, and 6 (x-1) = y ?

During a baseball game, when the player hits a homerun the ball does not receive a greater impulse because the momentum gained does not convert to greater impulse verse that exerted on the actual bat itself. The physics behind momentum do would not justify greater impulse on the baseball.