2. Define momentum
Define impulse
Relate impulse and momentum to everyday

3. In life - momentum describes something “on a roll” that is difficult to stop.
In physics - momentum describes a quantity of motion.
If an object is in motion then it has momentum.
"mass in motion"
Inertia
Velocity

4. Momentum is a vector quantity
Momentum is a vector quantity. It has the same direction as the objects velocity.
p = mv
Every moving object has momentum.
To bring the object to rest we must apply a force to change this momentum to zero.

8. Bus football sprinter skateboarder slapshot statue race car
Estimate the mass of each object and estimate its velocity to try to order the following objects in increasing momentum:
statue
Bus
football
sprinter
skateboarder
race car
slapshot

9. PHYSICS
A textbook at rest has no momentum. To make the book move you must overcome friction and the book’s inertia by applying a force.
A force accelerates the book, giving it a velocity. The book now has forward momentum, and the inertia of the book continues the motion forward.

10. Impulse
Momentum

11. To change an objects motion (momentum) we need to apply an unbalanced force.
Increased momentum
Unbalanced Force
Decreased momentum
Unbalanced Force

12. The amount of unbalanced force and the time during which the force is applied is the impulse.
I = F·t
Impulse equals force multipled by time F t

13. A force for a given amount of time will result in a mass undergoing a change in velocity.
m·∆v I =
F·t =
Impulse equals a change in momentum F t
0 m/s
10 m/s

14. 2 seconds
100 N
20 kg
0 m/s
10 m/s
F·t
m·∆v = =
100·2
200
20·10
200

15. F·t = m·∆v = -200 20·(-10) (-50)· -200 4 20 kg 50 N 10 m/s 0 m/s
4 seconds
50 N
20 kg
10 m/s
0 m/s
F·t =
m·∆v =
-200
20·(-10)
(-50)·
-200 4

16. TWO ways to apply a large impulse to an object and make a BIG change in momentum –
apply a LARGE force for a small time,
Impulse = (Force) (time)
apply a small force for LONG time.
Impulse = (Force) (time)

17. Stopping a passenger requires an impulse.
Inertia keeps the passenger moving forward with the same momentum as before (speed of the car).
Impulse = (Force) (time)
Stopping a passenger requires an impulse.
If the time can be made longer then the stopping force will be made smaller.
Small forces will cause fewer injuries to passenger.

18. In every sport where you hit something you are told to “follow through
Following through increases the TIME that your force acts on the object, which makes for a larger change in velocity (momentum)

20. ·t F m ∆v = m m 500 (.2) = + 200 m/s 0.5 500 (.1) = + 100 m/s 0.5
Follow through
0.5
500
(.1) =
+ 100 m/s
No follow
0.5