1. Lesson link
A balloon is filled up with hydrogen gas and then is released before being tied, explain why the balloon accelerates using Newton’s laws of motion

2. Draw a line under last lesson’s work and write today’s title in your book...
19/11/2018
c/w
Momentum

3. Engage Watch this video and then explain the following…
Why does the snowball get harder to stop?

4. Securing (4-6) Describe examples of momentum in collisions
Learning Objectives
Developing (3) Define momentum, recall and use the equation (momentum = mass x velocity)
Securing (4-6) Describe examples of momentum in collisions
Exceeding (7-9)
Apply Newton’s third law both to equilibrium situations and to collision interactions and relate it to the conservation of momentum in collisions

5. Principle of Conservation of Momentum
The total momentum before an event (collision or explosion) is equal to the momentum after
*Warning*
“Total” means if there is more than one object, then you add the momentums of the individual objects together.
Set up the air track with a stationary trolley in the middle (that has velcro attached). Knock another (also velcro’d) trolley towards it. Point out that they are assumed to stick together. Ask them to compare the initial velocity with that of both together (much slower in the end) why? The mass has become greater
Task: When you have watched the demonstration on the air track, write a small paragraph explaining what you observed

6. Collisions
Always divide the situation into before and after
What is the total momentum before the collision?
BEFORE
20ms-1
0ms-1
500kg
400kg
? ms-1
Therefore what is the total momentum after the collision?
AFTER
? Kg
So assuming they stick, what velocity do they travel off at?

7. Collisions 0ms-1 20ms-1 ? ms-1 ? Kg
When solving these, use your estimation skills and common sense. If the two objects collide, then the speed of them when attached together will likely be LESS than the fastest object.
BEFORE
Momentum before (P(b))
0ms-1
20ms-1
Object 1: m x v = kgms-1
Object 2: m x v = 0 kgms-1
Total:
= 10000kgms-1
500kg
400kg
AFTER
Momentum before (P(b)) = Momentum after(P(a))
? ms-1
? Kg
So momentum of both objects together must equal 10000kgms-1
Total mass is now 900kg
p= m x v
10000kgms-1 = 900kg x v
v= 10000/900 = 11.1ms-1

8. Draw diagrams with before and after to help!
Collision practice…
A 0.5 kg trolley is pushed at a velocity of 1.2ms-1 into a stationary trolley B of mass 1.5 kg. The two trolleys stick to each other after the impact. Calculate the velocity they travel at.
A 1000 kg rail wagon moving at a velocity of 5.0ms-1 on a level track collides with a 2ms kg wagon. The two wagons move together after the collision. Calculate the velocity they travel at.
Draw diagrams with before and after to help!
0.3ms-1, 3.2ms-1,
Try them out!

9. - Collisions: Head on! 20ms-1 12ms-1 ? ms-1
Always make the forward (to the right) direction positive! -
BEFORE
20ms-1
12ms-1
500kg
400kg
What information is missing from the velocity of the blue car?
AFTER
? ms-1
? Kg
Using the same approach, what is their velocity together?

10. - Collisions: Head on 20ms-1 12ms-1 ? ms-1 ? Kg BEFORE
Momentum before (P(b))
Object 1: m x v = kgms-1
Object 2: m x v = kgms-1
Total: (-4800)
= 5200kgms-1
500kg
400kg
AFTER
Momentum before (P(b)) = Momentum after(P(a))
? ms-1
So momentum of both objects together must equal 5200kgms-1
Total mass is now 900kg
p= m x v
5200kgms-1 = 900kg x v
v= 5200/900 = 5.78 ms-1
? Kg
FORWARD

11. Draw diagrams with before and after to help!
Collision practice…
A car of mass 1000 kg travels east at 30ms-1 and collides with a 3000kg truck traveling west at 20ms-1. What velocity do they have assuming they stick?
Draw diagrams with before and after to help!
0.3ms-1, 3.2ms-1,
Try them out!

12. Watch this video and then explain the following…
Engage
Watch this video and then explain the following…
Why does the gun recoil?

13. What is the total momentum before?
Explosions! BAM KAPOW BOOOOM
0ms-1
BEFORE
What is the total momentum before?
Gun: 1.2kg
Bullet: 0.005kg
400ms-1
AFTER
1.7ms-1 (bullet has p of 2kgms-1)
Momentum before (P(b)) = Momentum after(P(a))
So momentum of both objects together must equal 0kgms-1

14. Explosions! BAM KAPOW BOOOOM
Explosions! BAM KAPOW BOOOOM
? Kg
0ms-1
BEFORE
Momentum before (P(b))
Object 1 + 2:
m x v = 1.205kg x 0
Gun: 1.2kg
Bullet: 0.005kg
Total = 0kgms-1
400ms-1
AFTER
500kg
Task: If the bullet is speeding off, how is momentum conserved? Which law supports this?

15. Complete the Following
Evaluate
Complete the Following

16. Securing (4-6) Describe examples of momentum in collisions
Learning Objectives
Developing (3) Define momentum, recall and use the equation (momentum = mass x velocity)
Securing (4-6) Describe examples of momentum in collisions
Exceeding (7-9)
Apply Newton’s third law both to equilibrium situations and to collision interactions and relate it to the conservation of momentum in collisions