Topic 4 - Further Motion Concepts

• State the equation used to calculate an object's momentum.

  Momentum = Mass × Velocity
• What is the unit used for momentum?

  kg m/s

  Kilogram metres per seconds
• In a closed system, what can be said about the momentum before and after a collision?

  The total momentum before is equal to the total momentum afterwards.
• State an equation linking change in momentum, force and time.

  Force × Time = Change in Momentum

  F ∆t = m∆v
• The time taken for the change in momentum to occur is proportional to the...


  Resultant force felt by the object.

  (Newton's second law: F=ma, where mass × acceleration is the rate of change of momentum)
• What is an alternative name for the turning effect of a force?

  A moment.
• State the equation used to calculate the moment of a force. Give appropriate units.


  Moment of force = Force × Distance

  Moment (Nm), Force (N), Distance (m)
• What distance measurement is used when calculating a moment?

  The perpendicular distance from the pivot to the line of action of the force.
• If an object is in rotational equilibrium, what can be said about the moments acting on the object?

  The clockwise moments are equal to the anticlockwise moments.
• What do u, v and x stand for in the equations of motion?

  • u: initial velocity
  • v: final velocity
  • x: distance