6 Further mechanics

• what is conserved in a Elastic and Inelastic collision


  Momentum is conserved
• Elastic collisions

  Kinetic energy is conserved

  Collide and move away in opposite directions after collision

  Momentum is conserved
• Inelastic collisions

  Kinetic energy is not conserved

  Collide and stick together after collision

  Momentum is conserved
• Impulse

  Δp = F.Δt

  
  

  I = Δp = m(v-u)
• Angular velocity

  Rate of change of angular displacement

  
  

  ω = 2π/T

  
  

  v = ωr
• Centripetal acceleration


  Constant angular velocity and angular speed

  a = v^2/r

  
  

  a = Δv / t

  
  

  Δ v = ωt x v

  a = ωt x v / t

  a = ω x v

  v = ωr

  a = v / r x v

  a = v^2 / r
• Centripetal force 


  F = mv^2 / r
• Explain how banking allows the aeroplane to fly in a horizontal circular path

  Vertical component = weight of plane

  • Vertical component of resultant force is 0 so plane remains flying horizontally
  • Horizontal component of lift force acts as centripetal force
  • So it follows a circular path