Chapter 4 - Dynamics: Newton's Laws of Motion

Flexible Cord

That is, its size and dimensions are not taken into account Tension in a(n) ________ • Tension- The force a(n) ________ experiences when it is pulled on • We treat ________ as having "negligible mass "or mass so little that it does not have ot be taken into account 4.8 Problems Involving Friction, Inclines Friction • The surfaces of objects are not perfectly smooth, they have small imperfections and bumps that cause them to catch on each other when they slide together, the resistance of movement caused by surfaces is called friction and is a force • Kinetic Friction- Friction between two surfaces in motion, represented by Fk= µkFN Where Fk is the force of kinetic friction, µk is the coefficient of kinetic friction between the two surfaces, and FN is the normal force between the two surfaces • Static Friction- Friction between two surfaces that are not in motion, represented by Fs ≤ µsFN Where Fs is the force of static friction and µs • Note that the coefficients of kinetic and statics friction for the same surfaces can and most likely will be different, usually µs will be greater than µk • The force of static friction scales with your push until the maximum force is reached, represented by Fs= µsFN, once this limit is surpassed, kinetic friction will take over Inclines • Objects on an incline experience the force of gravity as a pushing force resisted by friction • The normal force experienced by an object on an incline is given by FN= mg cos θ WHere θ is the angle of the incline.

Force

A push or pull that causes an object to move

Newton's First Law of Motion

Every object continues in its state of rest, or of uniform velocity in a straight line, as long as no net force acts on it

Inertia

An object's tendency to maintain it's state of rest or uniform velocity

Mass

Measure of an object's inertia

Newton's Second Law of Motion

The acceleration of an object is directly proportional to the netforce acting on it, and is inversely proportional to the object’s mass.

Newton's Third Law of Motion

Whenever one object exerts a force on a second object, the second object exerts an equal force in the opposite direction of the first

Normal Force

A contact force that is perpendicular to the common surface of two objects

Free-Body Diagram

Way to represent forces acting on an object in order to determine the net force

Net Force

Vector sum of all forces on an object

Tension

The force a flexible cord experiences when pulled on

Kinetic Friction

Friction between two surfaces in motion

Static Friction

Friction between two surfaces not in motion