2. Momentum  Momentum is what Newton called the “quantity of motion” of an object.

3. Momentum  The momentum of an object:  Depends on the object’s mass.  Momentum is directly proportional to mass.  Depends on the object’s velocity.  Momentum is directly proportional to velocity.

4. Momentum  All objects have mass; so if an object is moving, then it has momentum - it has its mass in motion.  The amount of momentum which an object has is dependent upon two variables:  how much matter is moving?  how fast the matter is moving?

5. Momentum: "mass in motion” Equation: p = m x v Unit: kg*m/s Where; p = momentum m = Mass v = Velocity

6. Momentum (p)  In symbols:  Transcription Triangle p = mv m = ? v = ? p m v

7. Momentum  Momentum is a vector quantity.  Common units of momentum: kg m/s

8. Momentum Questions 2. A car possesses 20,000 units of momentum. What would be the car's new momentum if... a.) its velocity were doubled b.) its mass were doubled c.) both its velocity and mass were doubled p = 40,000 units p = 80,000 units

9. Ticket of Understanding  What are the variables to calculate the product of momentum?  What is the formula?

10. Momentum Questions 1. Determine the momentum of a... a.) 60 kg halfback moving eastward at 9 m/s. b.) 1000 kg car moving northward at 20 m/s. c.) 40 kg man moving southward at 2 m/s. p = 540 kg*m/s, east p = 20,000 kg*m/s, north p = 80 kg*m/s, south

14. If the boulder and the boy have the same momentum, will the boulder 1000 kg. crush the boy 35 kg.? EXPLAIN. Hint, Hint, Hint: Think about the momentum formula! p = mv

15. Impulse  The impulse exerted on an object depends on:  The force acting on the object.  Impulse is directly proportional to force.  The time that the force acts.  Impulse is directly proportional to time.

16. Impulse (I)  In symbols: I = Ft I F t

17. Impulse = change in momentum F  ∆t = ∆p = ∆(mv) F  ∆t = mv f - mv i F  ∆t = m (v f – v i ) ∆= Delta = Change f = final i = initial

18. Impulse  Impulse is a vector quantity.  Common units of impulse: N s

19. Impulse & Momentum  The impulse exerted on an object equals the object’s change in momentum.

20. Impulse & Momentum  In symbols: I =  p

21. Conservation of Momentum  Since impulse = change in momentum, If no impulse is exerted on an object, the momentum of the object will not change.

22. Conservation of Momentum  If no external forces act on a system, the total momentum of the system will not change.  Such a system is called an “isolated system”.

23. Conservation of Momentum  Momentum is conserved in every isolated system.

24. Conservation of Momentum  Another way to think about it is: Internal forces can never change the total momentum of a system.

25. Conservation of Momentum  In practice, for any event in an isolated system:  Momentum after = Momentum before

26. The End.