1. Science Starter What is the formula for momentum?
If there is a change in momentum, what does there need to be?
What do we call change in momentum?
What is the difference between an inelastic and elastic collision?
What is Newton’s 3rd Law?

2. Today’s Agenda Science Starter Kinetic Energy, Momentum, & Impulse
Example Problem & Lab Data Analysis
Kinetic Energy & Momentum HW

3. Kinetic Energy, Momentum, & Impulse
What is the formula for KE?
What are the units for KE?
KE is always present when _____
What causes a change in KE?
KE=(1/2)mv2
Joules (J)
There is movement!
An external force (just like change in momentum or impulse)

4. Example Problem #1 (Inelastic Collision)
A 2 kg block is moving 10 m/s to the right. The block collides and sticks to a 4kg block at rest. How much energy is generated during this collision?
System
Pi or KEi
Change (Δ)
Pf or KEf A
Pi=(2)(10)=20 kg.m/s
KEi=(1/2)(2)(10)2=100 J B
A+B

5. Example Problem #1 System A B A+B
A 2 kg block is moving 10 m/s to the right. The block collides and sticks to a 4kg block at rest. How much energy is generated during this collision?
System
Pi or KEi
Change (Δ)
Pf or KEf A
Pi=(2)(10)=20 kg.m/s
KEi=(1/2)(2)(10)2=100 J B
Pi=(4)(0)=0 kg.m/s
KEi=(1/2)(4)(0)2=0 J
A+B

6. Example Problem #1 System A B A+B
A 2 kg block is moving 10 m/s to the right. The block collides and sticks to a 4kg block at rest. How much energy is generated during this collision?
System
Pi or KEi
Change (Δ)
Pf or KEf A
Pi=(2)(10)=20 kg.m/s
KEi=(1/2)(2)(10)2=100 J B
Pi=(4)(0)=0 kg.m/s
KEi=(1/2)(4)(0)2=0 J
A+B
Pi= = 20 kg.m/s
KEi= = 100J

7. Example Problem #1 System A B A+B
A 2 kg block is moving 10 m/s to the right. The block collides and sticks to a 4kg block at rest. How much energy is generated during this collision?
System
Pi or KEi
Change (Δ)
Pf or KEf A
Pi=(2)(10)=20 kg.m/s
KEi=(1/2)(2)(10)2=100 J
Pf=(2)(Vf)=20 kg.m/s
KEi=(1/2)(2)(Vf)2=100 J B
Pi=(4)(0)=0 kg.m/s
KEi=(1/2)(4)(0)2=0 J
A+B
Pi= = 20 kg.m/s
KEi= = 100J

8. Example Problem #1 System A B A+B
A 2 kg block is moving 10 m/s to the right. The block collides and sticks to a 4kg block at rest. How much energy is generated during this collision?
System
Pi or KEi
Change (Δ)
Pf or KEf A
Pi=(2)(10)=20 kg.m/s
KEi=(1/2)(2)(10)2=100 J
Pf=(2)(Vf)=20 kg.m/s
KEi=(1/2)(2)(Vf)2=100 J B
Pi=(4)(0)=0 kg.m/s
KEi=(1/2)(4)(0)2=0 J
Pi=(4)(Vf)=20 kg.m/s
KEi=(1/2)(4)(Vf)2=100 J
A+B
Pi= = 20 kg.m/s
KEi= = 100J

9. Example Problem #1 System A B A+B
A 2 kg block is moving 10 m/s to the right. The block collides and sticks to a 4kg block at rest. How much energy is generated during this collision?
System
Pi or KEi
Change (Δ)
Pf or KEf A
Pi=(2)(10)=20 kg.m/s
KEi=(1/2)(2)(10)2=100 J
Pf=(2)(Vf)=20 kg.m/s
KEi=(1/2)(2)(Vf)2=100 J B
Pi=(4)(0)=0 kg.m/s
KEi=(1/2)(4)(0)2=0 J
Pi=(4)(Vf)=20 kg.m/s
KEi=(1/2)(4)(Vf)2=100 J
A+B
Pi= = 20 kg.m/s
KEi= = 100J
Pf=Pi  (2+4)Vf=20

10. Example Problem #1 System A B A+B
A 2 kg block is moving 10 m/s to the right. The block collides and sticks to a 4kg block at rest. How much energy is generated during this collision?
System
Pi or KEi
Change (Δ)
Pf or KEf A
Pi=(2)(10)=20 kg.m/s
KEi=(1/2)(2)(10)2=100 J
Pf=(2)(3.3)=6.7 kg.m/s
KEi=(1/2)(2)(3.3)2=11 J B
Pi=(4)(0)=0 kg.m/s
KEi=(1/2)(4)(0)2=0 J
Pi=(4)(3.3)=13.3 kg.m/s
KEi=(1/2)(4)(3.3)2=22 J
A+B
Pi= = 20 kg.m/s
KEi= = 100J
Pf=Pi  (2+4) 3.3=20
KEi= =33 J

11. Example Problem #1 System A B A+B
A 2 kg block is moving 10 m/s to the right. The block collides and sticks to a 4kg block at rest. How much energy is generated during this collision?
System
Pi or KEi
Change (Δ)
Pf or Kef A
Pi=20 kg.m/s
KEi=100 J
Pf=6.7 kg.m/s
KEi=11 J B
Pi=0 kg.m/s
KEi=0J
Pi=13.3 kg.m/s
KEi=22 J
A+B
Pi= 20 kg.m/s
KEi= 100J
Pf=20
KEi=33 J

12. Example Problem #1 System A B A+B
A 2 kg block is moving 10 m/s to the right. The block collides and sticks to a 4kg block at rest. How much energy is generated during this collision?
System
Pi or KEi
Change (Δ)
Pf or Kef A
Pi=20 kg.m/s
KEi=100 J
ΔP= =-13.3 kg.m/s
ΔKE= =89 J
Pf=6.7 kg.m/s
KEi=11 J B
Pi=0 kg.m/s
KEi=0J
Pi=13.3 kg.m/s
KEi=22 J
A+B
Pi= 20 kg.m/s
KEi= 100J
Pf=20
KEi=33 J

13. Example Problem #1 System A B A+B
A 2 kg block is moving 10 m/s to the right. The block collides and sticks to a 4kg block at rest. How much energy is generated during this collision?
System
Pi or KEi
Change (Δ)
Pf or Kef A
Pi=20 kg.m/s
KEi=100 J
ΔP= =-13.3 kg.m/s
ΔKE= =89 J
Pf=6.7 kg.m/s
KEi=11 J B
Pi=0 kg.m/s
KEi=0J
ΔP=13.3-0=13.3 kg.m/s
ΔKE= 22-0= 22 J
Pi=13.3 kg.m/s
KEi=22 J
A+B
Pi= 20 kg.m/s
KEi= 100J
Pf=20
KEi=33 J

14. Example Problem #1 System A B A+B
A 2 kg block is moving 10 m/s to the right. The block collides and sticks to a 4kg block at rest. How much energy is generated during this collision?
System
Pi or KEi
Change (Δ)
Pf or Kef A
Pi=20 kg.m/s
KEi=100 J
ΔP= =-13.3 kg.m/s
ΔKE= =89 J
Pf=6.7 kg.m/s
KEi=11 J B
Pi=0 kg.m/s
KEi=0J
ΔP=13.3-0=13.3 kg.m/s
ΔKE= 22-0= 22 J
Pi=13.3 kg.m/s
KEi=22 J
A+B
Pi= 20 kg.m/s
KEi= 100J
ΔP=20-20= 0 kg.m/s
ΔKE= = -67J
Pf=20
KEi=33 J

15. Lab Data Analysis
Look at the data you have for your scenarios from Tuesday and calculate the change in momentum and kinetic energy for the entire system
Confirm that elastic conserves P & KE
Confirm that inelastic conserves P, but not KE
Complete for at least 2 Elastic & 1 Inelastic

16. Initial Conditions Outcome Conditions Object 1 Object 2 Mass Vel. Mom
Elastic or Inelastic
Outcomes
Outcome Conditions
Object 1
Object 2
Mass
Vel.
Mom
O O

17. System Object 1 Object 2 1&2 Pi or KEi Change (Δ) Pf or KEf
Initial Conditions
Elastic or Inelastic
Outcomes
Outcome Conditions
Object 1
Object 2
Mass
Vel.
Mom
O O
System
Pi or KEi
Change (Δ)
Pf or KEf
Object 1
Object 2
1&2

18. Kinetic Energy & Momentum HW
Work on completing tables and answering the questions when your table is complete!