Chapter 7

• Newtons first law of motion:


  An object will remain at rest or continue to move with a constant velocity unless acted upon by a resultant force
• Newtons third law of motion


  When two objects interact, they exert equal and opposite forces on each other.
• Momentum


  $p=$$mv$
• The principal of conservation of energy states for an system of interacting objects, the total momentum in a specified direction remains constant , as long as no external forces act on the system
• In a perfectly elastic collision, momentum is conserved, total energy is conserved and total kinetic energy is conserved.
• In an inelastic collision, momentum is conserved, total energy is conserved and total kinetic energy is not conserved
• Newtons second law of motion:


  The net force acting on an object is directly proportional to the rate of change of momentum and is in the same direction

  
  

  $F =$$\frac {\Delta p}{\Delta t}$
• Forces which are accelerating or decelerating an object usually change over time can be analysed using the idea of impulse
• Impulse is the product of force and the time which this force acts on an object
• Impulse is equal to the area under of a force-time graph