FORCES

• what is a scalar quantity


  have magnitude and no direction
• whats magnitude


  size
• what is a vector quantity 


  has magnitude and direction
• example of scalar


  speed, distance temperature mass, time
• example of vector


  force, velocity acceleration momentum and displacement
• whats a force


  is a push or pull that acts on an object due to the interaction with another object
• what is a contact force


  two object physically touching
• what is a non contact force


  objects not physically touching, physically separated
• example of a contact force


  friction, air resistance, tension in ropes
• example of non contact forces

  magnetic force, gravitational force, electrostatic force
• what is weight

  weight is a force acting on an object due to gravity
• what is the force caused by?


  the gravitational field strength around the earth
• what is mass


  the amount of matter in an object
• what does gravitational field strength vary with


  location, stronger the closer you are to the mass causing the field and stronger for larger masses
• what is weight measured with


  newtons- unit

  measured with a spring balance
• weight equals


  weight=massxgfs
• what is the resultant force


  the number of force acting on an object may be replaced by a single force that has the same effect as all the original forces acting together
• how is work done on an object with a force


  when a force causes an object to move through a distance work is done on the object so a force does work on an object when the force causes a displacement the object
• formula of work done


  force x distance
• what is elastic deformation


  if an elastic has been deformed it can go back to its primal shape and length after the force has been removed (elastic objects)
• what is inelastic deformation

  if an object has been inelastically deformed it doesn't return to its original shape and length after force has moved
• extension is


  directly proportional to force
• equation of force


  force = springconstant x extenstion
• what does the spring constant depend on

  the material you are stretching affects the spring constant

  for example, the stiffer= greater spring constant
• Limit of Proportionality


  The range within which Hooke's Law holds true, within which the force required to stretch/compress an elastic material is directly proportional to the distance/displacement from equilibrium.
• what is a moment

  the turning effect is called the moment of the force
• formula for moment of a force

  moment= force x distance (perpendicular distance)
• if an object is balanced

  the total clockwise moment about a pivot equals the total anticlockwise moment about that pivot
• what do leavers do to the distance to the pivot

  increase it, at the point of the pivot where the force is applied

  this means less force is needed to get the same moment
• what are leavers good at


  they make it easier to do work
• features of gears


  transmit rotational effects

  gears are circular discs with 'teeth'

  their teeth interlock so that the turning one causes another to turn in the opposite direction

  they are used to transmit the rotational effects of a force from one place to another
• how can u change a moment with a gear

  with a different sized gears
• if a force is transmitted to a larger gear..

  it will cause a bigger moment as the distance to the pivot is greater
• what is a fluid

  a fluid is a substance that can flow because their particles are able to move around a fluid

  can be liquid or gas
• what does the pressure in fluids cause

  a normal (a right angles) to an surface
• formula for pressure

  pressure = force normal to surface/area of that surface m^2
• what does pressure in an liquid depend on

  depth and density
• liquids have a what density


  uniform
• the more dense means what for pressure?

  increase in pressure as particles are more compact
• formula for pressure= height of the column of liquid(m) x

  gravitational field strength (n/kg) x density of the liquid (kg/m^3)