Cycle 1 Review Sheet, Part 1 25 August 2014 From time to time this semester I will hand out a “review sheet” which is a condensed summary of what I consider some of the more important topics and key concepts from the lectures. Remember in this class, the lectures define the range of content that you are responsible for, not the text. This is especially pertinent because of the cyclical nature of the class. If I indicate a point here in a review sheet this means that this is something I want to emphasize. 1-D Kinematics: Definitions: vave ≡ ∆x ∆t Definition of average velocity, defined over an interval. v ≡ dx dt Definition of instantaneous velocity. aave ≡ ∆v ∆t Definition of average acceleration, defined over an interval. a ≡ dv dt = d 2x …show more content…
For this part of the course we will apply Newton’s Law in one dimension at a time only. We will generally use the Cartesian subscripts “x” or “y” to indicate the relevant dimension we are considering. For example when we want to talk about the component of the net force in the x-direction, we represent this as the vector component Fx. Note that we never put little arrows on components. We can just write the 1-D version of Newton’s Second Law: Fx = max where ax is the acceleration defined positive in the x-direction. Finally note that the variable m what is called “mass” refers to the inertia of a body. In other words m tells you how hard it is to acceleration something. It’s harder to get a freight train to accelerate than it is to get a mosquito to accelerate. We always call m the mass, not the weight. Newton’s Third Law: Law of Action-Reaction: If there exists a force on body A due to body B: F~ AB then the body A must also exert a force F~ BA on body B so that these two forces have the same magnitude: FAB = FBARevised Physics 121 Fall 2014 Document #05 – Cycle 1 Review Sheet, Part 1 page 5 of