Physics for Engineers

• PHYSICAL QUANTITIES

  Any number that is used to describe a physical

  phenomenon quantitatively using a standard measurable

  unit or units.
• SCALAR QUANTITIES

  Quantities that are described by only a single number which is its

  Magnitude.
• VECTOR QUANTITIES

  Quantities that are described by both magnitude and the

  direction in space.
• Resultant Can be determined in two ways:

  1. Graphical Methods
  2. Analytical Methods
• Graphical Methods

  These involve plotting and drawing the vectors (using a

  convenient scale) and directly measuring the resultant

  from these vectors.
• Analytical Methods

  These involve no scaled drawings. These are purely

  computation that mostly involves trigonometry.

  Provides the most accurate value for the resultant.
• VECTOR RESOLUTION

  A process of combining two or more vectors acting at the

  same point on an object to determine a single equivalent

  vector known as the “Resultant” vector.
• Polygon Method

  The resultant is determined by laying the vectors tail to head in series. Once the last vector is

  in placed, the resultant is drawn from the tail of the origin vector up to the tip of the last

  vector.
• Displacement

  A vector quantity that is the change in

  position of an object.
• Velocity

  A vector quantity that is the rate of change in

  position (displacement) over a time interval
• Speed

  is the scalar part or the magnitude of velocity
• Relative Velocity

  The observed velocity of an object with

  respect or relative to where the observer is (frame of

  reference of the observer)
• UNIT VECTORS

  a vector whose magnitude is equal to one

  and dimensionless. They are used to specify a determined

  direction or simply pointer vectors.