This document discusses the law of conservation of momentum and collisions. It defines elastic and inelastic collisions. In an elastic collision, the objects bounce off each other after collision and momentum and kinetic energy are conserved. In an inelastic collision, the objects stick together after collision and only momentum is conserved. The law of conservation of momentum states that the total momentum of an isolated system before a collision equals the total momentum after the collision.

1. LAW OF CONSERVATION OF
MOMENTUM AND COLLISIONS

2. After the collision, what do you
think will happen?

3. NEWTON’S THIRD LAW OF MOTION
“For every action,
there’s an equal but
opposite reaction.”

4. F1
F1 = -F2
F2
t1 = t2
F1t1= -F2t2
I1 = -I2

5. F1
I1 = -I2
F2
p1 = -p2
∑pbefore = ∑pafter

6. BEFORE AFTER
m1 m2 m1 m2
v1 v2
v1’ v2’
∑pbefore = ∑pafter
p1 + p2 = p1’ + p2’
m1v1 + m2v2 = m1v1’ + m2v2’

7. LAW OF CONSERVATION OF MOMENTUM
“In an isolated system, the
momentum before the
collision is equal to the
momentum after the
collision”
RENE DESCARTES

8. COLLISIONS
-occur when two or
more objects hit
each other

9. TWO TYPES OF COLLISION
Elastic Collision Inelastic Collision
-after the collision,
the two objects did
not stick together.
- after the collision,
the two objects stick
together.

10. Type of
Collision
Diagram Behavior of
Objects
Conserved
Quantity
Before After
ELASTIC
The two
objects
bounce
after the
collision.
Momentum
Kinetic
Energy

11. Type of
Collision
Diagram Behavior of
Objects
Conserved
Quantity
Before After
INELASTIC
The two
objects
stick
together
after the
collision.
Momentum
V’

12. APPLICATION OF CONCEPTS

13. Which is safer to do when
the brake of the car is lost,
bump the car into a
haystack or to a concrete
wall? Justify your answer.

14. How would you explain
scientifically the use of
airbags and seatbelts in
cars?

15. In boxing, “riding the punch” is
a technique used by boxers to
minimize the effect of a punch.
Explain how this technique
really helps the boxer.