One Dimensional Kinematics Overview

Introduction

One goal of physics is to model and predict the behavior of objects. Using only two of our fundamental units, time and displacement we will build a framework to predict the motion of objects. We will start with one dimension in this unit and expand to two dimensions in the next unit. This allows for reasonably accurate descriptions of the motion objects in time such as a car screeching to a stop, a ball thrown upward or a boulder dropped from the edge of a cliff. Our models will be expressed both graphically and algebraically. We will start off slowly with a number of simplifying assumption to make our tasks easier, many of which will be refined to predict more accurate results in more complex settings later in this course and in future physics courses.

Essential Questions

What are the definitions of displacement and distance?
What are the definitions of velocity and speed?
What is the difference between average velocity and instantaneous velocity?
What is the definition of acceleration?
What are the four kinematic equations?
What are three assumptions built into the kinematic equations?
What characteristic of a displacement versus time graph represents velocity?
What characteristic of a velocity versus time graph represents acceleration?
What characteristic of an acceleration versus time graph represents velocity?
What characteristic of a velocity versus time graph represents displacement?
What assumptions are made about acceleration in freefall problems?
Are objects either thrown up, or thrown down considered to be in freefall?
When is the final velocity equal to zero in a freefall problem?
Which quantities are vectors, which are scalars in the kinematic equations?

Key Terms

acceleration - The rate at which the velocity of an object changes with respect to time.
acceleration due to gravity - The acceleration on an object caused by being near another object with mass, usually a much larger object (for an object interacting with the Earth), -9.8 m/s² near the surface of the earth, diminishing to zero very far from the earth.
average velocity -
delta - Quantity minus the initial quantity, represented by ∆.
distance - The length of the pathway from the starting point to the ending point.
displacement - A vector quantity describing is the shortest distance from the initial to the final position of an object and the direction.
freefall - Any motion of an object where gravity is the only force acting upon it.
instantaneous velocity -
speed - The velocity of the pathway from the starting point to the ending point.
velocity - The rate at which the displacement of an object changes with respect to time.

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