momentum

• what is momentum?

  a property of an object's motion. It is defined by the equation

  momentum = mass x velocity
• what is the principle of conservation of momentum?

  In a closed system (nothing else affecting the objects) the total momentum before an interaction is equal to the total momentum after the interaction
• What is force?

  the rate of change of momentum
• How do crash mats and air bags work?

  By increasing the time taken for the same change in momentum, we decrease the force acting on the object.
• For the same force applied on a ball, increasing the time of contact (by following through) means the ball has a larger change in momentum and it therefore travels faster and further
• Why is it important to include features such as crumple zones in cars?

  so that it increases the time taken for the same change in momentum, so it decreases the force acting upon the car to reduce injury of the people in the car
• what is the formula linking mass, momentum and velocity?

  momentum = mass x velocity
• explain how the rate of change of momentum links to the force applied in a collision

  in collisions, force depends on how fast the momentum changes. Faster change = bigger force, slower change = smaller force
• How would you explain how cushioning/pads can protect the object during a collision

  Force = m    v / t   The force is reduced as the time to stop is increased

   

                                   less force means less injury.