So I have problem with understanding graphs in kinematics. Right now I am solving one task and it goes like this : Solution : a) positive , because of positive slope of tangent b) negative c) at 3 and 5 d) a2=a6 > a3=a5 > a1=a4 Magnitudes of the acceleration are the greatest at points 2 and 6. Magnitudes of the acceleration at points 3 and 5 are eaqual and lesser than magnitudes at points 2 and 6. At points 1 and 4 magnitudes of the acceleration is 0. This is how it is in solution and this is how I understood it ( If it is not ok please correct me or tell me how it should be ) : By some logic this curve is starting at positive part of graph and it is growing until point 1 ( so particle is moving forward and it is accelerating) and suddenly at point 1 acceleration is equal zero ( This is in solution, a=0 and it is confusing me ). So it was moving ,at point 1, with constant velocity and now as curve goes, the particle started slowing down until point 3 ( so it was moving forward but slowing down because it has negative acceleration ). At point 3 direction of moving is changing and now the particle is moving backwards ( I guess because it was slowing down now velocity is negative and it is moving backwards and accelerating ) until point 4. At point 4 as it is said in solution a=0 so now particle is moving with constant velocity. From 4 to 5 it is has acceleration and the particle is moving forward but in negative area ( this is sooo much confusing me. Does this mean that it has negative velocity but positive acceleration, and if it has, how come it is changing direction at point 5 ? I just cant imagine this ) And as it is said in solution at point 5 it changes direction, and now it is accelerating foward with positive acceleration. So what is confusing me is : 1)This with changing direction of moving, How particle was moving from point 4 to point 5 ? 2) Are the magnitudes of the negative acceleration at point 2 and positive acceleration at point 6 greatest? 3) Should particle stop moving when it has acceleration and it suddenly wants to start moving slowly ? 4) If it is slowing down and then changes direction of moving it doesnt have to stop ?