Motion with Constant Velocity and Zero Net Force
Summary: We introduce a simply model based on Newton's revolutionary insight - that the natural state of motion of an isolated body is motion with constant velocity.We now explore our first model - motion with constant velocity. According to Newton, this is the natural state of motion. If the net external force acting on a body is zero, the body will move with constant velocity (with respect to an inertial coordinate system).
Mathematically, motion with constant velocity is quite straightforward: the velocity is constant and the position increases linearly with time. The hard part is sometimes to determine why the net force is zero when some forces are more obvious than others.
Introduction to the ModelDescription and Assumptions
This model is applicable to a single point particle moving with constant velocity, which implies that it is subject to no net force (zero acceleration). Equivalently, the model applies to an object moving in one-dimension whose position versus time graph is linear. It is a subclass of the One-Dimensional Motion with Constant Acceleration model defined by the constraint a = 0. Learning ObjectivesStudents will be assumed to understand this model who can:
S.I.M. Structure of the ModelCompatible SystemsA single point particle (or a system treated as a point particle with position specified by the center of mass). Relevant InteractionsIn order for the velocity to be constant, the system must be subject to no net force. Law of ChangeMathematical Representation
Diagrammatic Representations
Relevant ExamplesExamples Involving Purely One-Dimensional MotionExamples Involving Determining when Two Objects MeetExamples Involving Projectile MotionAll Examples Using This Model |
