Physics AS definitions

  1. Acceleration
    Change in velocity divided by time taken
  2. Speed
    Distance travelled divided by time taken
  3. Velocity
    Displacement divided by time taken
  4. Displacement
    The straight line distance from a reference point in a single specified direction
  5. Vector
    Quantities that have both magintude and direction
  6. Scalar
    Quantities that are fully defined by by magnitude only
  7. Equilibrium
    • No resultant force
    • No resultant moment
  8. Moment
    Force multiplied by the perpendicular distance from the line of action of the force to the pivot
  9. Principle of moments
    Sum of clockwise moments is equal to sum of anti-clockwise moments when the object is in equilibrium about the same pivot
  10. Centre of gravity
    The single point where the entire weight of a body appears to act
  11. Couple
    A pair of equal and opposite forces whose lines of action do not coincide
  12. Torque of a couple
    One of the forces multiplied by the perpendicular distance between the forces
  13. Density
    Mass divided by volume
  14. Pressure
    Force divided by area
  15. Spring constant
    Force divided by extension
  16. Hooke's Law
    Extension is directly proportional to force provided the elastic limit has not been exceeded
  17. Stress
    Force divided by cross-sectional area
  18. Strain
    Extension divided by original length
  19. Young's Modulus
    Tensile stress divided tensile strain
  20. Ductile material
    Can be easily and permenantly stretched into thin wires
  21. Elastic
    Materials return to their original shape and size when the applied force is removed
  22. Elastic limit
    The maximum load up to which the material can regain its original shape and size when the load is removed
  23. Plastic
    Material does not return to its original shape and size when the load is removed
  24. Weight
    The force of gravity on the mass of a body
  25. Joule
    The work done when a force of 1N moves its point of application by 1m in the direction of the force
  26. Kinetic energy
    The energy of a body due to movement

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  27. Newton
    The force needed to give an acceleration of 1ms-2 to a mass of 1kg
  28. Graviational potential energy
    The energy a body has due to its position

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  29. Power
    Work done divided by time
  30. Work
    Force multiplied by distance moved in the direction of the force
  31. Braking distance
    Distance travelled from when the brakes are applied until the car comes to a stop
  32. Thinking distance
    • Distance travelled during the drivers reaction time before the brakes are applied
    • =speed x reaction time
  33. Stopping distance
    Thinking distance + braking distance
  34. UTS
    The maximum stress a material can withstand before fracture
  35. Strain energy (3 methods)
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    • Area under F-x graph
  36. Thinking distance
    = speed x reaction time
  37. Gradient of displacement-time graph
  38. Gradient of a velocity-time graph
  39. Area under a velocity-time graph
Card Set
Physics AS definitions
Physics AS definitions