Physics (Newton's law of Motion)

• Particle is an idealized body that occupies only a single point in space, has mass and has no internal structure.
• Rigid body is a collection of particles linked by a light rigid framework.
• Reference frame is a rigid body (e.g. Earth) whose particles can be labeled to create reference points. It is simplified by introducing a coordinate system (e.g. Cartesian)
• Types of Motion

  • Translational Motion
  • Rotational Motion
  • Rolling Motion
  • Vibrational or Oscillatory Motion
  • Brownian
• Translational motion – linear motion (i.e. rectilinear and curvilinear motions)
• • Rotational motion – rotary motion about an axis
• Rolling motion – combined rotation and translation
• Vibrational or Oscillatory motion – harmonic or periodic motion
• Brownian – chaotic or random motion
• What newton's Everybodylaw is this?

  Every body continues in its state of rest, or of uniform motion in a straight line, unless it is compelled to change that state by forces impressed upon it

  first law
• What newton's law is this?

  The change of motion is proportional to the motive force impressed and is made in the direction of the line in which that force is impressed.

  second law
• what newton's law is this?

  To every action there is always imposed an equal reaction; or, the mutual actions of two bodies upon each other are always equal and directed to contrary parts

  third law
• law of inertia


  There exists in nature a unique class of mutually unaccelerated reference frames (the inertial frames) in which the First Law is true.
• Types of Inertia

  • Inertia of rest
  • Inertia of translation
  • Inertia of rotation
• Inertia of rest : It is the inability of a body to change its state of rest by itself
• Inertia of translation : It is inability of a body to change its state of uniform translational motion by itself
• Inertia of rotation : It is inability of a body to rotate by itself
• Net Force and Acceleration


  The acceleration of an object is directly proportional to the net force on the object
• A constant net force causes a constant acceleration

  
• Doubling the net force doubles the acceleration

  
• Having the net force halves the acceleration

  
• SI unit of force

  N - newton
• SI unit of mass

  kg - kilogram
• SI unit of Acceleration

  m/s^2
• A force is an interaction between two objects or between an

  object and its environment.

  • A force is a vector quantity, with magnitude and direction
• Types of Forces

  • Contant
  • Non-contact
• The weight of an object (on the Earth) is the

  the gravitational force that the Earth exerts on it.
• The weight W of an object of mass m is:

  W = mg
• Normal force: When an object pushes on a surface, the surface pushes back

  on the object perpendicular to the surface.
• Tension: A pulling force exerted on an object by ideal strings (massless,

  frictionless, unbreakable, and inextensible) and is always measured

  parallel to the string on which it applies.
• Coulomb's Frictional Forces


  Occurs when a surface resists sliding of an object and is parallel to the surface
• Static friction acts when there is no relative motion between bodies
• Kinetic friction acts when a body slides over a surface.
• Rolling Friction

  The opposing force that comes into existence when one object rolls over the

  surface of another object is known as rolling friction
• The fluid resistance or drag force on a body depends on the speed of the body
• A falling body reaches its terminal speed vt when the resisting force equals the weight of the body
• Free Body Diagram (FBD)


  A single body or a subsystem of bodies isolated from its surroundings showing all the external forces acting on its free body diagram
• Unstable equilibrium – the

  the object moves even farther

  from its original position
• Stable equilibrium – the object returns to its original position
• Neutral equilibrium – the object remains in its new position