Force and motion

• Speed - is how fast you’re going
• velocity - the speed of something in a given direction
• Acceleration - how quickly velocity is changing
• 1. 2
  2. 35
  3. 0.5
  4. 40m

  
• Gravity - is the force of attraction between all masses
• Weight - is cause by the pull of gravity
• Mass - is the amount of stuff in a object
• Unit

  Gravity- ( N/Kg )

  weight- ( Newtons )

  Mass- ( Kg )
• 1st law of motion - balanced forces means no change in velocity
• 2nd law of motion - a resultant force means acceleration

  L
• Contact forces -

  Air resistance

  Tension

  Thrust

  Friction
• Non contact forces

  Electrostatic

  Magnetic

  Nuclear

  Gravitational
• Contact - direct contact
• Non contact - act over a distance
• Scalars - only magnitude no direction
• Vectors - has magnitude and direction
• Scalar examples - speed and mass
• Vector examples - velocity and acceleration
• Terminal velocity - maximum speed
• Friction - is a force that opposes motion between two surfaces that are touching.
• Friction - slows things down or stops them
• Friction acts in the opposite direction
• Balanced forces

  A resultant force of zero
• Braking distance

  Distance a vehicle travels while breaking
• distance time graph

  Shows distance change over time
• Distance

  How far a object moves
• Distortion

  Change in object size or shape die to a force
• Elastic deformation

  Temporary change In shape. Object returns to orginal shape when force is removed
• Elastic limit

  Maximum force an object can take before permanent deformation
• Equilibrium

  An object in equilibrium when the resultant force and moment are both zero
• Hooks law

  The extension of a spring is directly proportional to the force applied to it, up to the limit of proportionally
• Human reaction time

  The time it takes for the brain to react to a stimulus
• Limit of proportionally

  Point where extension is no longer proportional to force
• Linear relationship

  When two variables increase at a constant rate, forming a straight line on a graph
• Newton meter

  Tool to measure force
• Plastic deformation

  A permeant deformation
• Resultant force

  One force that replaces all others and has the same effect.
• Spring Constant:

  spring stiffness. Higher value = less stretch
• Stopping Distance: Thinking distance + braking distance.
• Thinking Distance: Distance travelled during driver’s reaction time.