DO NOWCLEAN UP CLEAN UPEVERYBODYEVERYWHERECLEAN UPCLEAN UPEVERYBODYDO YOUR SHARE

On the back of the sticky note that I give you, write down a question on any topic from

chapters 1 through 5 (we are in chapter 6 now). The question

can be long or short and require a word or math answer. Write on the front of the sticky note a 1 if

your question is easy, 2 if it’s average, and 3 if it’s hard.

Get into groups of 4 or 5.

Gather your notes and a calculator.

Week Agenda:

Class 1 – return lab reports, conservation of momentum, introduce collisions

Class 2 – elastic and inelastic collisions, demonstrations

Class 3 – review for testClass 4 – chapter 6 test

Let’s Review!

What is momentum?What is the conservation of energy?

What is Newton’s 3rd law?

So, what is the conservation of momentum?

Conservation of Momentum

~ the total momentum of all objects interacting with one another remains constant

~ (m1v1 + m2v2)i = (m1v1 +

m2v2)f

~ change in momentum of object one equals the opposite change in momentum of object two (Newton’s 3rd law)

~ (m1v1)f – (m1v1)i = –(m2v2)f –

(m2v2)i

In the game of pool, the cue ball collides with colored billiard balls. The mass of all billiard balls is 160 grams. Pretend a billiard stick hits the cue ball and causes it to move 4.50 meters per second. Then, the cue ball hits the green ball that is resting on the pool table. If the velocity of the cue ball is 0.110 meters per second after the collision, what is the velocity of the green ball after the collision?

How does the game of pool relate to the conservation of momentum?

Homework

Practice DPage 209 # 1

Section ReviewPage 211 # 3

AGENDA

1)Go over homework2)Take notes3)Demonstrate collisions!

Inelastic Collision

~ a collision in which two objects deform in a collision and move separately

~ (m1v1 + m2v2)i = (m1v1 +

m2v2)f

~ p IS conserved~ KE is NOT conserved

Perfectly Inelastic Collision

~ a collision in which two objects stick together after colliding

~ (m1v1 + m2v2)i = (m1 +

m2)vf

~ p IS conserved~ KE is NOT conserved

Elastic Collision

~ a collision in which two objects move separately after colliding

~ (m1v1 + m2v2)i = (m1v1 +

m2v2)f

~ p IS conserved~ KE IS conserved

How many perfectly inelastic collisions do you see?

How many elastic collisions

do you see?

Homework

What are two examples* of perfectly inelastic collisions?

What are two examples* of inelastic collisions?

What are two examples* of elastic collisions?

* not discussed in class

Kelvin and Richard are racing on Roosevelt Boulevard. Kelvin is going 102 mph and Richard is going 3 mph slower. The mass of Kelvin and his car is 700 kg and Richard and his car are ¾ that mass. If they both press the brakes with 15,000 N, how long does it take them each to stop?

1 mi = 1,609 m

In the game of pool, the cue ball collides with colored billiard balls. The mass of the cue balls is 170 grams and the mass of the yellow ball is 160 grams. Pretend a billiard stick hits the cue ball and causes it to move 5.40 meters per second. Then, the cue ball hits the yellow ball that is resting on the pool table. If the velocity of the cue ball is 0.111 meters per second after the collision, what is the velocity of the yellow ball after the collision?

Create a question about…

momentum and/or impulse (1st row)

conservation of momentum (2nd row)

collisions (3rd row) equations (4th row) (I’ll review math questions)