Physics Pointers

• Physics


  The science that deals with the properties and interrelationships of matter and energy, excluding chemical and biological changes. It includes the study of force, motion, heat, light, sound, electricity, magnetism, radiation, and atomic energy.
• Coordinate system


  • A mathematical method used to represent the position of points
  • On the x-axis, anything to the right of the origin is considered positive and anything to the left is considered negative
  • On the y-axis, anything above the origin is positive and below the origin is negative
• Distance (d)


  A scalar quantity that measures the interval between two locations measured along the actual path connecting them
• Displacement (d)


  A vector quantity that measures the interval between two locations measured along the shortest path connecting them
• Speed (v)


  The rate of motion, or the rate of change of position of an object over time
• Average speed (v)


  Distance Traveled (d) / Time of Travel (t)
• Velocity (v)


  The rate of linear motion of an object in a particular direction over time
• Average Velocity (v)


  Displacement (d) / Time of Travel (t)
• Acceleration (a)


  The rate of change of velocity over time
• Average Acceleration (a)


  Change in Velocity (v) / Time of Travel (t)
• Newton's Law of Universal Gravitation


  Any two bodies in the universe attract each other with a force that is directly proportional to the product of the masses of the two bodies and inversely proportional to the square of the distance between them
• Projectile


  • An object or body thrown with an initial velocity and whose motion is influenced by the pull of gravity
  • Trajectory: The path of a projectile that follows through space
  • Gravitational free-fall: The motion of an object vertically downward with initial velocity of zero
• Vertical Displacement


  y = yo + Voyt + 1/2 at^2
• Horizontal Displacement


  x = xo + Voxt
• Vertical Velocity


  Voy + at
• Newton's First Law of Motion (Law of Inertia)


  • A body will remain in its state of rest or in uniform motion along a straight line unless acted upon by an outside force
• Newton's Second Law of Motion (Law of Acceleration)


  • A net force acting on the body produces an acceleration which is in the direction of the force, and is directly proportional to the force and inversely proportional to the mass of the body
• Weight (W)


  The measure of the gravitational force of an object
• Mass (m)


  The measure of the resistance of an object to change its state of motion
• Newton's Third Law of Motion (Law of Interaction)


  • For every force, there is an equal and opposite force
• Momentum


  The product of the mass of an object and its velocity
• Impulse


  The product of the force and the time during which the force acts on the body
• Torque


  A force that tends to produce rotation about an axis
• Translational motion


  • Motion in which a body or object moves along a linear axis rather than a rotational axis
• Rotational motion


  • Motion in which an object rotates about an axis
• Centripetal force


  The force that causes an object to be accelerated towards the circle's center
• Friction


  • A force which acts between surfaces of objects in contact where one or both objects move or are about to move relative to each other
  • Static or Starting Friction: The frictional force generated when one surface starts to slide across another surface
  • Kinetic or Sliding Friction: The frictional force acting when the body is in motion
  • Rolling Friction: The friction between two surfaces when one surface is rolling over another
• Work


  The product of the magnitude of the force exerted on an object and the displacement that the object moves while the force is being exerted
• Kinetic energy (KE)


  The energy of motion, given by the equation KE = 1/2 mv^2
• Potential energy (PE)


  The energy of position or stored energy, given by the equation PE = mgh
• Law of Conservation of Energy


  • The sum of all forms of energy within an isolated system is constant. Energy is conserved and can neither be created nor destroyed, only converted from one form to another.
• Heat transfer by conduction


  • The most significant means of heat transfer in a solid, where heat passes from one molecule to another without the molecules moving
• Heat


  One form of energy which can come from different sources. It is thermal energy which may be absorbed or given off by an object, causing a change in its volume.
• Heat transfer


  1. Conduction

  2. Convection

  3. Radiation
• Conduction


  The most significant means of heat transfer in a solid. Molecules conduct the heat but they themselves do not move.
• Convection


  Usually the dominant form of heat transfer in fluids. A warmer thing comes along and displaces a colder thing.
• Radiation


  The only form of heat transfer that occurs in the absence of any medium (i.e., through a vacuum). Hot bodies give off heat in the form of electromagnetic waves.
• Fusion


  The process of changing the substance from its solid phase to its liquid phase. The temperature at which fusion takes place is the melting point.
• Vaporization


  The process of changing a liquid to its vapor state. The temperature at which vaporization takes place is the boiling point.
• Temperature


  An expression of heat content. It is not exactly a measure of heat.