Hello, I have a few questions with some things I can’t seem to grasp. 1. If objects *without* any force being applied to them move at a constant velocity, which might be zero, .... and objects being *acted* on by a force are always accelerating. What causes an object being acted on by some force to gain a constant velocity if its initial velocity is zero? Meaning that, am i right in thinking the above is impossible, as you can only begin to move forwards from an initial velocity of zero, with positive acceleration which only occurs once you overcome opposing forces. Then and only then can you lower your force to equal opposing forces to have a constant acceleration. So constant velocity from an initial velocity of zero cannot occur, some form of acceleration has to occur first. 2. With regard to friction, from my understanding, friction is a force in the opposing direction or travel, that is some force to the strength of all forces acting perpendicular to the direction of travel. If this is so, if i have a horizontal surface, with a ball with an infinitely small force being applied to it to make it move to the right. How come that ball isn’t being pushed in the negative direction of travel by the force of friction? Which in this case will be a pretty large force of f = FrictionConstant*mg, in the negative direction of travel. 3. I keep seeing graphs of friction as slopes that go up as the static friction is being reached, and then slowly back down as static friction is overcome, and dynamic friction becomes the opposing force. Why the slope down as we finally overcome static friction? Seeing as its a constant, wouldn’t it be more of a step down? Im sure that all of the above is a lack understanding on my part. And so as a final request, can anyone recommend a book on vector physics? (i believe is the term) That is, im interested in learning things like how changing the lengths marked in red of the following structure changes its state as to whether or not it collapses, and how removing things like the cross bar bit affects it.