Physics paper two

• Contact Forces


  • Tension force
  • Friction force
  • Normal contact force
• Non-contact Forces


  • Gravitational force
  • Electrostatic force
  • Magnetic force
• Force


  A push or pull that acts upon an object as a result of that object's interactions with its surroundings
• Force


  Measured in newtons, has both magnitude and direction because it is a vector quantity
• Air resistance


  A contact force due to the physical contact (collisions) between an object and the particles in the air
• Scalar quantity


  Only has a magnitude and does not have a direction
• Scalar quantities


  • Distance
  • Speed
  • Temperature
• Vector quantities


  • Weight
  • Displacement
  • Velocity
• Free body diagrams


  • Use arrows to show all of the forces acting on an object
  • The length of each arrow indicates the magnitude of that force
  • The direction of each arrow indicates the direction of the force
• Elastic deformation


  An object returns to its original shape after the forces have been removed
• Inelastic deformation (or plastic deformation)


  An object does not return to its original shape after the forces have been removed
• Extension


  The increase in length of a spring when it's stretched (can also refer to a decrease in length if the spring is compressed)
• Spring constant


  A measure of how many Newtons of force it would require to stretch (or compress) the object by 1 metre, has the units N/m
• Hooke's Law


  The extension of an object is directly proportional to the force applied, described by the formula F=ke
• A higher spring constant means the spring is more firm, a lower spring constant means the spring is less firm
• When a spring is stretched

  Energy is transferred to its elastic potential energy store
• When the spring is released

  Most of that energy is transferred to kinetic energy
• Acceleration


  The rate of change in velocity
• Terminal velocity


  Reached when the resultant force is 0 and when the weight has the same magnitude as the air resistance - when both have reached equilibrium
• Newton's first law


  • A resultant force is required to change the motion of an object
  • A moving object that has no resultant force acting upon it will continue moving at the same velocity
• Newton's second law


  • A resultant force will cause an object to accelerate in the direction of the force
  • The object maintaining constant velocity cannot be caused by a resultant force acting on a object
  • The formula is F = ma
• Newton's third law


  • When two objects interact, the forces they exert on each other are equal and opposite
• Stopping distance


  The total distance a car travels from the moment when the driver first notices an obstruction, to when the car stops
• Stopping distance = thinking distance + braking distance
• Alcohol, drugs, tiredness and being distracted all slow a person's reaction time
• Ice on the road, worn tyre tread and worn brakes all increase braking distance
• Momentum


  Described by the formula p = mv
• The total momentum before a collision is equal to the total momentum after the collision
• Wavelength


  The distance of one entire oscillation of a wave
• Amplitude


  The maximum displacement from the equilibrium position (the x-axis)
• Time period


  The time it takes for one entire oscillation of a wave
• Transverse wave


  • The oscillations are perpendicular to the direction of energy transfer
• Longitudinal wave


  • The oscillations are parallel to the direction of energy transfer
• In reflection


  Angle of incidence is always equal to the angle of reflection
• Specular reflection


  Occurs on surfaces when the boundary is flat and produces a clear image
• Diffuse reflection


  Occurs on materials when the surface is bumpy which means you cannot usually see your reflection
• What can happen to waves

  • Reflected
  • Absorbed
  • Transmitted
  • Reflected
• Refraction


  The change in direction of a wave, as it passes from one medium to another, and is caused by its change in speed
• Light travelling from a less dense material, into a more dense material

  Will bend towards the normal
• Radiowaves


  • Have a long wavelength and a low frequency
  • Are created with an alternating current