Two Dimensional Kinematics

Image of a motocross rider doing a trick in the air with the text: Two Dimensional Kinematics

Introduction

So do we really only move in one dimension? Not very often. Although there are times we move in a straight line, most of the time we move in two or three dimensions. A car driving up a hill is moving in two dimensions at a time and an airplane that is climbing and turning is moving in three. So how do we describe the motion of these machines? First we must understand the concept of a vector in two dimensions and how to solve for this kind of motion. Then we look at two specific examples of two-dimensional motion, the motion of a projectile and uniform circular motion.

Module Lessons Preview

In this module, we will study the following topics:

How do I calculate the component of a vector?
How do I find the resultant of two vectors?
How do we describe the two-dimensional motion of a projectile?
What makes uniform circular motion different from projectile motion?

Key Terms

Centripetal: Directed toward the center.
Centripetal Acceleration: Acceleration directed perpendicular to the velocity of a moving object that changes the direction of the object, but not the magnitude of the velocity.
Components: The sides of the right triangle defined when the vector is the hypotenuse of a right triangle with sides along the x and y axis.
Cross Product: The product of a vector times a vector that results in a vector value.
Dot Product: The product of a vector times a vector that results in a scalar value.
Resultant: The vector that is the sum of two or more vectors.
Projectile: Any object traveling through space (the air) under only the influence of gravity, that is with no acceleration in the horizontal axis and accelerated at 9.80 m/s² in the negative vertical axis.
Two-Dimensional Motion: Motion that must be defined as having components in two different axes.
Scalar: A value that can be completely defined with only a number and a unit.
Tangential Velocity: The velocity of an object that is in circular motion that is directed at a tangent to the arc of the object's path.
Uniform Circular Motion: Movement of an object that keeps a constant velocity but travels in a pathway that has a constant radius from a point.
Vector: A value that must have both a magnitude (number value with a unit) and a direction.

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