Springs

• Potential energy = mass x g x height

  PE = mgh

  J = kg x N/kg x m
• Kinetic energy = 0.5 x mass x speed2

  KE = 0.5mv2

  J = 0.5 x kg x m/s2
• Work done = force x distance

  W = Fd

  J = N x m
• Power = work done / time

  P = W / t

  W = J / s
• Force exerted by a spring = extension x spring constant

  F = xk

  N = m x N/m
• Hooke's Law


  Describes the relationship between a force and the extension of a spring
• Investigation Hooke's Law

  1. Hang your spring from a clamp stand
  2. Measure the length of the spring
  3. Add mass to the bottom of your spring
  4. Measure the new length of the spring
  5. Repeat step 3 and 4 as many times as you need
  6. Plot a graph of force against extension and draw a line of best fit
  7. A straight line of best fit obeys Hookes Law

  
• Energy transferred in stretching = 0.5 x spring constant x extension2

  E = 0.5kx2

  J = 0.5 x N/m x m2