P2

• Elasticity


  Property of an object that allows it to deform when a force is applied and then return to its original shape and size when the force is removed
• Spring constant


  Measure of the amount of force required to stretch an object by 1 metre
• Hooke's law


  The force required to stretch or compress a spring is proportional to the distance the spring is stretched or compressed
• Deformed object


  • Plastic deformation
  • Elastic deformation
• Plastic deformation


  Object does not return to its original shape and size when the force is removed
• Elastic deformation


  Object returns to its original shape and size when the force is removed
• Extension


  Increase in length of a spring when it is stretched
• Increase in force on a spring

  Extension increases proportionately
• Hooke's law


  Force and extension have a linear relationship
• Elastic limit


  Limit beyond which Hooke's law no longer applies and the object is permanently deformed
• Forces applied to an object

  • Bending
  • Stretching
  • Compressing
• Higher spring constant objects

  • Require more force to stretch by the same amount
• Hydraulic system


  1. Downward force on piston 1

  2. Liquid experiences pressure

  3. Pressure force transmitted equally in all directions

  4. Upward force on piston 2
• Moment


  Rotational or turning effect of a force
• Momentum


  Force x distance
• Lever


  Device that transmits the turning effect of a force
• Lever


  • Input and output forces on different sides of pivot
  • Output force closest to pivot is larger
• Gear


  Device that transmits turning effects, rotating in opposite directions
• Gear


  • Larger radius gear has proportionately larger turning effect
• Scalar

  • only have magnitude
  • speed, mass, temperature, time
• Vector

  • Magnitude (size) and direction
  • Displacement, velocity, acceleration and force
• $V =$$s/t$


  Velocity= displacement / time

  • negative velocity to show moving backwards
• $S =$$d/t$


  Speed = distance / time
• Acceleration


  rate in change of velocity
• Acceleration 


  $a=$$ΔV/t$

  ΔV= change in velocity

  t= time

  
  

  a= V-U/t

  U - initial velocity

  V - final velocity
• Acceleration with distance equation

  2as= $V^2 - U^2$

  a= acceleration

  s= distance

  V= final

  U= initial
• Gravitational force 


  9.8 m/s
• Distance/ time graph 


  > How far something has traveled

  > Gradient shows speed

  > straight line- constant

  > Flat line- Stationary

  > increasing gradient- acceleration

  > Decreasing gradient- deceleration
• Velocity/ time graph 


  > Shows velocity change over time

  Acceleration= Change in velocity/ change in time

  > Flat- steady velocity

  > Steeper greater the acceleration of deceleration

  > Curve- change in acceleration

  > Area under graph= distance
• Contact

  • two objects touching
  • Friction, air resistance, Tension, normal contact force
• Non-contact

  • don't require objects to touch
  • Gravitational, magnetic, electrostatic
  • Field of influence around the object
• Resultant force

  • overall force on an object after cancellation
• Newtons first law

  • An object will remain stationary or at a constant velocity unless acted upon by external force
• Newton's second law 


  F=ma

  F= force (n)

  m= mass (kg)

  a= acceleration (m/s)$^2$
• Inertia

  • motion of an object to remain unchanged
• Inertial mass = force/ acceleration
• Terminal velocity 


  Velocity remains constant
• Friction

  • slow objects down/ stop
  • Force= friction =constant speed
  • Force > Friction= accelerate
  • Force < Friction = decelerate
• Falling objects reaching terminal velocity

  1. more driving force than friction so they accelerate
  2. Resistance is directly proportional to velocity
  3. As velocity increases so does friction
  4. reducing acceleration till friction force is equal to driving so it doesn't accelerate anymore
  5. No resultant force
  6. Reach max terminal velocity
• Terminal velocity dependent on drag

  • Greater the drag the lower the terminal velocity
  • Drag depends on shape and area