4.2 Change in Momentum and Impulse

Describe the impulse delivered to an object or system.

• The rate of change of a system’s momentum is equal to the net external force exerted on that system. Relevant equation: F dp dt net =  
• Impulse is defined as the integral of a force exerted on an object or system over a time interval. Relevant equation:
• Impulse is a vector quantity and has the same direction as the net force exerted on the system.
• The impulse delivered to a system by a net external force is equal to the area under the curve of a graph of the net external force exerted on the system as a function of time.
• The net external force exerted on a system is equal to the slope of a graph of the momentum of the system as a function of time. TOPIC 4.2 Change in Momentum and Impulse

Describe the relationship between the impulse exerted on an object or system and the change in momentum of the object or system.

• Change in momentum is the difference between a system’s final momentum and its initial momentum. Relevant equation:
• The impulse–momentum theorem relates the impulse delivered to an object and the object’s change in momentum.
  • i. The impulse exerted on an object is equal to the object’s change in momentum. Relevant equation:
  • ii. Newton’s second law of motion is a direct result of the impulse–momentum theorem applied to systems with constant mass. F dp dt m dv dt manet == =    
  • iii. The impulse–momentum theorem also describes the behavior of a system in which the velocity is constant but the mass changes with respect to time. F dp dt dm dt vnet ==   