SlideShare a Scribd company logo
1 of 13
Download to read offline
Physics 101:  Lecture 12 Collisions and Explosions ,[object Object],Exam II
Overview of Semester ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]
Collisions Explosions ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],Procedure “ before” “ after” m 1 m 2 m 1 m 2 “ before” “ after” M m 1 m 2
ACT ,[object Object],[object Object],[object Object],[object Object],[object Object],Demo with gliders    P initial  =    P final M V = M V f  + M V f V = 2V f V f  = V/2
ACT ,[object Object],[object Object],Mechanical Energy = Kinetic Energy + Potential E = ½ m v 2  + 0 K initial  = ½ m v 2   K final  = ½ m (v/2) 2  + ½ m (v/2) 2  = ¼ m v 2 ,[object Object],[object Object],[object Object],CORRECT
Preflight 1 & 2 ,[object Object],[object Object],[object Object],“ Two cars crashing in a perfect inelastic collision.” “ If two African laden swallows were flying towards each other with an equal magnitude of momentum, and they collided completely inelastically, becoming a monster two-headed African laden swallow, then the total kinetic energy after the collision is zero, and the sum of the momentums is also zero.” Demo with gliders CORRECT
Ballistic Pendulum H L L L L m M A projectile of mass  m  moving horizontally with speed  v  strikes a stationary mass  M  suspended by strings of length  L .  Subsequently,  m   +   M   rise to a height of  H .  Given  H ,  M  and  m  what is the initial speed  v  of the projectile? M + m v V V =0 See I.E. 1 in homework   demo Collision Conserves Momentum 0+m v = (M+m) V After, Conserve Energy ½ (M+m) V 2 +0 = 0+(M+m) g H V = sqrt(2 g H) Combine:
Explosions ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],v 1 v 2 A=1, B=2, C=same 0 = p 1 +p 2 p 1 = -p 2 “ before” “ after” M m 1 m 2
Collisions or Explosions in Two Dimensions ,[object Object],[object Object],[object Object],y x before after
Explosions ACT “ before” A B Which of these is possible? (Ignore friction and gravity) A B C =both D = Neither “ after” P x  = 0 and P y  = 0  P x  = 0, but   P y  > 0  P x  = 0, and   P y  = 0 M
Center of Mass ,[object Object],in my stomach doughnuts don't have a center of mass because they are removed and sold as doughnut hole The fact that that doughnut is "yummy" is debatable if you ask me. I prefer mine with chocolate frosting and some sort of filling. The center of mass then is much easier to figure out. It's clearly the center of the jelly or custard filling area. Center of Mass = Balance point Center of Mass!
Center of Mass Center of Mass of a system behaves in a   SIMPLE   way - moves like a  point particle ! - velocity of CM is unaffected by collision if F ext  = 0 (pork chop demo) P tot  = M tot V cm F ext  t =   P tot  = M tot  V cm So if F ext  = 0 then V cm  is constant   Also:  F ext  = M tot a cm
Summary ,[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

More Related Content

What's hot

Analyzing forcedgms
Analyzing forcedgmsAnalyzing forcedgms
Analyzing forcedgmslweinmann
 
Potensial Energy
Potensial EnergyPotensial Energy
Potensial Energynerraaini
 
IGCSE Pysics Momentum
IGCSE Pysics MomentumIGCSE Pysics Momentum
IGCSE Pysics MomentumJen Soriano
 
Day 40 Ppt Batfink Momentum
Day 40 Ppt Batfink MomentumDay 40 Ppt Batfink Momentum
Day 40 Ppt Batfink Momentumffiala
 
04-14-08 - Momentum And Impulse
04-14-08 - Momentum And Impulse04-14-08 - Momentum And Impulse
04-14-08 - Momentum And Impulsewjerlinger
 
5.80 ppt batfink momentum
5.80 ppt batfink momentum5.80 ppt batfink momentum
5.80 ppt batfink momentumffiala
 
032616 week3 momentum_and_impulse
032616 week3 momentum_and_impulse032616 week3 momentum_and_impulse
032616 week3 momentum_and_impulseSubas Nandy
 

What's hot (18)

Lecture09
Lecture09Lecture09
Lecture09
 
Lecture02
Lecture02Lecture02
Lecture02
 
Lecture10
Lecture10Lecture10
Lecture10
 
Lecture16
Lecture16Lecture16
Lecture16
 
Ap review total
Ap review totalAp review total
Ap review total
 
Lecture14
Lecture14Lecture14
Lecture14
 
Chapter 9
Chapter 9Chapter 9
Chapter 9
 
Lecture03
Lecture03Lecture03
Lecture03
 
Analyzing forcedgms
Analyzing forcedgmsAnalyzing forcedgms
Analyzing forcedgms
 
Potensial Energy
Potensial EnergyPotensial Energy
Potensial Energy
 
Lecture08
Lecture08Lecture08
Lecture08
 
IGCSE Pysics Momentum
IGCSE Pysics MomentumIGCSE Pysics Momentum
IGCSE Pysics Momentum
 
Day 40 Ppt Batfink Momentum
Day 40 Ppt Batfink MomentumDay 40 Ppt Batfink Momentum
Day 40 Ppt Batfink Momentum
 
04-14-08 - Momentum And Impulse
04-14-08 - Momentum And Impulse04-14-08 - Momentum And Impulse
04-14-08 - Momentum And Impulse
 
5.80 ppt batfink momentum
5.80 ppt batfink momentum5.80 ppt batfink momentum
5.80 ppt batfink momentum
 
Lecture04
Lecture04Lecture04
Lecture04
 
Newton's second law
Newton's second lawNewton's second law
Newton's second law
 
032616 week3 momentum_and_impulse
032616 week3 momentum_and_impulse032616 week3 momentum_and_impulse
032616 week3 momentum_and_impulse
 

Viewers also liked

Viewers also liked (20)

Lecture20
Lecture20Lecture20
Lecture20
 
Gas Law
Gas LawGas Law
Gas Law
 
Lecture25
Lecture25Lecture25
Lecture25
 
Lect01 handout
Lect01 handoutLect01 handout
Lect01 handout
 
Lecture16
Lecture16Lecture16
Lecture16
 
Acids & Bases
Acids & BasesAcids & Bases
Acids & Bases
 
Lecture13
Lecture13Lecture13
Lecture13
 
Lecture22
Lecture22Lecture22
Lecture22
 
Lecture26
Lecture26Lecture26
Lecture26
 
Lect05 handout
Lect05 handoutLect05 handout
Lect05 handout
 
Lecture28
Lecture28Lecture28
Lecture28
 
Lecture23
Lecture23Lecture23
Lecture23
 
Lecture29
Lecture29Lecture29
Lecture29
 
Lecture19
Lecture19Lecture19
Lecture19
 
Lect04 handout
Lect04 handoutLect04 handout
Lect04 handout
 
Dalton’s law
Dalton’s lawDalton’s law
Dalton’s law
 
Deriving the ideal gas law
Deriving the ideal gas lawDeriving the ideal gas law
Deriving the ideal gas law
 
Lecture24
Lecture24Lecture24
Lecture24
 
Lecture18
Lecture18Lecture18
Lecture18
 
06 dalton’s law of partial pressures
06 dalton’s law of partial pressures06 dalton’s law of partial pressures
06 dalton’s law of partial pressures
 

Similar to Lecture12

As and A Level mumentum.ppt
As and A Level mumentum.pptAs and A Level mumentum.ppt
As and A Level mumentum.pptssuser5087b61
 
Lecture Ch 07
Lecture Ch 07Lecture Ch 07
Lecture Ch 07rtrujill
 
Krisna suryanti rsa1 c314011 fis pgmipau
Krisna suryanti rsa1 c314011 fis pgmipauKrisna suryanti rsa1 c314011 fis pgmipau
Krisna suryanti rsa1 c314011 fis pgmipaukrisnasuryanti
 
2 momentum notes (all)
2 momentum notes (all)2 momentum notes (all)
2 momentum notes (all)cpphysicsdc
 
Momentum and Energy.pptx
Momentum and Energy.pptxMomentum and Energy.pptx
Momentum and Energy.pptxZamzam660728
 
Work and energy part a
Work and energy part aWork and energy part a
Work and energy part aAngelo Aquino
 
032616 week3 impulse_and_momentum
032616 week3 impulse_and_momentum032616 week3 impulse_and_momentum
032616 week3 impulse_and_momentumSubas Nandy
 
Lecture Ch 06
Lecture Ch 06Lecture Ch 06
Lecture Ch 06rtrujill
 
2.4 analysing momentum
2.4 analysing momentum2.4 analysing momentum
2.4 analysing momentumShahadah Rahim
 
2.4 momentum & energy 2017
2.4 momentum & energy 20172.4 momentum & energy 2017
2.4 momentum & energy 2017Paula Mills
 
Long 50slideschapter 5 motion notes [autosaved]
Long 50slideschapter 5 motion notes [autosaved]Long 50slideschapter 5 motion notes [autosaved]
Long 50slideschapter 5 motion notes [autosaved]Duluth Middle
 

Similar to Lecture12 (20)

As and A Level mumentum.ppt
As and A Level mumentum.pptAs and A Level mumentum.ppt
As and A Level mumentum.ppt
 
Lecture Ch 07
Lecture Ch 07Lecture Ch 07
Lecture Ch 07
 
impuls and momentum
impuls and momentumimpuls and momentum
impuls and momentum
 
Krisna suryanti rsa1 c314011 fis pgmipau
Krisna suryanti rsa1 c314011 fis pgmipauKrisna suryanti rsa1 c314011 fis pgmipau
Krisna suryanti rsa1 c314011 fis pgmipau
 
2 momentum notes (all)
2 momentum notes (all)2 momentum notes (all)
2 momentum notes (all)
 
C:\fakepath\momentum
C:\fakepath\momentumC:\fakepath\momentum
C:\fakepath\momentum
 
Momentum
MomentumMomentum
Momentum
 
Lecture11
Lecture11Lecture11
Lecture11
 
Hp 06 win
Hp 06 winHp 06 win
Hp 06 win
 
Hp 06 Win
Hp 06 WinHp 06 Win
Hp 06 Win
 
Momentum and Energy.pptx
Momentum and Energy.pptxMomentum and Energy.pptx
Momentum and Energy.pptx
 
Every Equation
Every EquationEvery Equation
Every Equation
 
Work and energy part a
Work and energy part aWork and energy part a
Work and energy part a
 
Momentum
MomentumMomentum
Momentum
 
032616 week3 impulse_and_momentum
032616 week3 impulse_and_momentum032616 week3 impulse_and_momentum
032616 week3 impulse_and_momentum
 
Lecture Ch 06
Lecture Ch 06Lecture Ch 06
Lecture Ch 06
 
2.4 analysing momentum
2.4 analysing momentum2.4 analysing momentum
2.4 analysing momentum
 
Lecture20
Lecture20Lecture20
Lecture20
 
2.4 momentum & energy 2017
2.4 momentum & energy 20172.4 momentum & energy 2017
2.4 momentum & energy 2017
 
Long 50slideschapter 5 motion notes [autosaved]
Long 50slideschapter 5 motion notes [autosaved]Long 50slideschapter 5 motion notes [autosaved]
Long 50slideschapter 5 motion notes [autosaved]
 

More from oyunbileg06

More from oyunbileg06 (20)

семинар6
семинар6семинар6
семинар6
 
семинар5
семинар5семинар5
семинар5
 
семинар4
семинар4семинар4
семинар4
 
семинар3
семинар3семинар3
семинар3
 
семинар2
семинар2семинар2
семинар2
 
семинар1
семинар1семинар1
семинар1
 
Tsahilgaan buleg3
Tsahilgaan buleg3Tsahilgaan buleg3
Tsahilgaan buleg3
 
Thermodynamic buleg2
Thermodynamic buleg2Thermodynamic buleg2
Thermodynamic buleg2
 
Phys1 test
Phys1 testPhys1 test
Phys1 test
 
Mekhanic buleg1
Mekhanic buleg1Mekhanic buleg1
Mekhanic buleg1
 
Phys1 lecture
Phys1 lecturePhys1 lecture
Phys1 lecture
 
Phys1 hutulbur
Phys1 hutulburPhys1 hutulbur
Phys1 hutulbur
 
Phys1 bie daalt
Phys1 bie daaltPhys1 bie daalt
Phys1 bie daalt
 
Lect28 handout
Lect28 handoutLect28 handout
Lect28 handout
 
Lect27 handout
Lect27 handoutLect27 handout
Lect27 handout
 
Lect26 handout
Lect26 handoutLect26 handout
Lect26 handout
 
Lect25 handout
Lect25 handoutLect25 handout
Lect25 handout
 
Lect24 handout
Lect24 handoutLect24 handout
Lect24 handout
 
Lect22 handout
Lect22 handoutLect22 handout
Lect22 handout
 
Lect21 handout
Lect21 handoutLect21 handout
Lect21 handout
 

Recently uploaded

KubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCost
KubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCostKubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCost
KubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCostMatt Ray
 
UiPath Community: AI for UiPath Automation Developers
UiPath Community: AI for UiPath Automation DevelopersUiPath Community: AI for UiPath Automation Developers
UiPath Community: AI for UiPath Automation DevelopersUiPathCommunity
 
Anypoint Code Builder , Google Pub sub connector and MuleSoft RPA
Anypoint Code Builder , Google Pub sub connector and MuleSoft RPAAnypoint Code Builder , Google Pub sub connector and MuleSoft RPA
Anypoint Code Builder , Google Pub sub connector and MuleSoft RPAshyamraj55
 
Building Your Own AI Instance (TBLC AI )
Building Your Own AI Instance (TBLC AI )Building Your Own AI Instance (TBLC AI )
Building Your Own AI Instance (TBLC AI )Brian Pichman
 
UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...
UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...
UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...UbiTrack UK
 
Artificial Intelligence & SEO Trends for 2024
Artificial Intelligence & SEO Trends for 2024Artificial Intelligence & SEO Trends for 2024
Artificial Intelligence & SEO Trends for 2024D Cloud Solutions
 
VoIP Service and Marketing using Odoo and Asterisk PBX
VoIP Service and Marketing using Odoo and Asterisk PBXVoIP Service and Marketing using Odoo and Asterisk PBX
VoIP Service and Marketing using Odoo and Asterisk PBXTarek Kalaji
 
NIST Cybersecurity Framework (CSF) 2.0 Workshop
NIST Cybersecurity Framework (CSF) 2.0 WorkshopNIST Cybersecurity Framework (CSF) 2.0 Workshop
NIST Cybersecurity Framework (CSF) 2.0 WorkshopBachir Benyammi
 
Videogame localization & technology_ how to enhance the power of translation.pdf
Videogame localization & technology_ how to enhance the power of translation.pdfVideogame localization & technology_ how to enhance the power of translation.pdf
Videogame localization & technology_ how to enhance the power of translation.pdfinfogdgmi
 
How Accurate are Carbon Emissions Projections?
How Accurate are Carbon Emissions Projections?How Accurate are Carbon Emissions Projections?
How Accurate are Carbon Emissions Projections?IES VE
 
Designing A Time bound resource download URL
Designing A Time bound resource download URLDesigning A Time bound resource download URL
Designing A Time bound resource download URLRuncy Oommen
 
Introduction to Matsuo Laboratory (ENG).pptx
Introduction to Matsuo Laboratory (ENG).pptxIntroduction to Matsuo Laboratory (ENG).pptx
Introduction to Matsuo Laboratory (ENG).pptxMatsuo Lab
 
Building AI-Driven Apps Using Semantic Kernel.pptx
Building AI-Driven Apps Using Semantic Kernel.pptxBuilding AI-Driven Apps Using Semantic Kernel.pptx
Building AI-Driven Apps Using Semantic Kernel.pptxUdaiappa Ramachandran
 
ADOPTING WEB 3 FOR YOUR BUSINESS: A STEP-BY-STEP GUIDE
ADOPTING WEB 3 FOR YOUR BUSINESS: A STEP-BY-STEP GUIDEADOPTING WEB 3 FOR YOUR BUSINESS: A STEP-BY-STEP GUIDE
ADOPTING WEB 3 FOR YOUR BUSINESS: A STEP-BY-STEP GUIDELiveplex
 
UiPath Studio Web workshop series - Day 7
UiPath Studio Web workshop series - Day 7UiPath Studio Web workshop series - Day 7
UiPath Studio Web workshop series - Day 7DianaGray10
 
IESVE Software for Florida Code Compliance Using ASHRAE 90.1-2019
IESVE Software for Florida Code Compliance Using ASHRAE 90.1-2019IESVE Software for Florida Code Compliance Using ASHRAE 90.1-2019
IESVE Software for Florida Code Compliance Using ASHRAE 90.1-2019IES VE
 
Meet the new FSP 3000 M-Flex800™
Meet the new FSP 3000 M-Flex800™Meet the new FSP 3000 M-Flex800™
Meet the new FSP 3000 M-Flex800™Adtran
 
Cybersecurity Workshop #1.pptx
Cybersecurity Workshop #1.pptxCybersecurity Workshop #1.pptx
Cybersecurity Workshop #1.pptxGDSC PJATK
 
20230202 - Introduction to tis-py
20230202 - Introduction to tis-py20230202 - Introduction to tis-py
20230202 - Introduction to tis-pyJamie (Taka) Wang
 
The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...
The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...
The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...Aggregage
 

Recently uploaded (20)

KubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCost
KubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCostKubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCost
KubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCost
 
UiPath Community: AI for UiPath Automation Developers
UiPath Community: AI for UiPath Automation DevelopersUiPath Community: AI for UiPath Automation Developers
UiPath Community: AI for UiPath Automation Developers
 
Anypoint Code Builder , Google Pub sub connector and MuleSoft RPA
Anypoint Code Builder , Google Pub sub connector and MuleSoft RPAAnypoint Code Builder , Google Pub sub connector and MuleSoft RPA
Anypoint Code Builder , Google Pub sub connector and MuleSoft RPA
 
Building Your Own AI Instance (TBLC AI )
Building Your Own AI Instance (TBLC AI )Building Your Own AI Instance (TBLC AI )
Building Your Own AI Instance (TBLC AI )
 
UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...
UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...
UWB Technology for Enhanced Indoor and Outdoor Positioning in Physiological M...
 
Artificial Intelligence & SEO Trends for 2024
Artificial Intelligence & SEO Trends for 2024Artificial Intelligence & SEO Trends for 2024
Artificial Intelligence & SEO Trends for 2024
 
VoIP Service and Marketing using Odoo and Asterisk PBX
VoIP Service and Marketing using Odoo and Asterisk PBXVoIP Service and Marketing using Odoo and Asterisk PBX
VoIP Service and Marketing using Odoo and Asterisk PBX
 
NIST Cybersecurity Framework (CSF) 2.0 Workshop
NIST Cybersecurity Framework (CSF) 2.0 WorkshopNIST Cybersecurity Framework (CSF) 2.0 Workshop
NIST Cybersecurity Framework (CSF) 2.0 Workshop
 
Videogame localization & technology_ how to enhance the power of translation.pdf
Videogame localization & technology_ how to enhance the power of translation.pdfVideogame localization & technology_ how to enhance the power of translation.pdf
Videogame localization & technology_ how to enhance the power of translation.pdf
 
How Accurate are Carbon Emissions Projections?
How Accurate are Carbon Emissions Projections?How Accurate are Carbon Emissions Projections?
How Accurate are Carbon Emissions Projections?
 
Designing A Time bound resource download URL
Designing A Time bound resource download URLDesigning A Time bound resource download URL
Designing A Time bound resource download URL
 
Introduction to Matsuo Laboratory (ENG).pptx
Introduction to Matsuo Laboratory (ENG).pptxIntroduction to Matsuo Laboratory (ENG).pptx
Introduction to Matsuo Laboratory (ENG).pptx
 
Building AI-Driven Apps Using Semantic Kernel.pptx
Building AI-Driven Apps Using Semantic Kernel.pptxBuilding AI-Driven Apps Using Semantic Kernel.pptx
Building AI-Driven Apps Using Semantic Kernel.pptx
 
ADOPTING WEB 3 FOR YOUR BUSINESS: A STEP-BY-STEP GUIDE
ADOPTING WEB 3 FOR YOUR BUSINESS: A STEP-BY-STEP GUIDEADOPTING WEB 3 FOR YOUR BUSINESS: A STEP-BY-STEP GUIDE
ADOPTING WEB 3 FOR YOUR BUSINESS: A STEP-BY-STEP GUIDE
 
UiPath Studio Web workshop series - Day 7
UiPath Studio Web workshop series - Day 7UiPath Studio Web workshop series - Day 7
UiPath Studio Web workshop series - Day 7
 
IESVE Software for Florida Code Compliance Using ASHRAE 90.1-2019
IESVE Software for Florida Code Compliance Using ASHRAE 90.1-2019IESVE Software for Florida Code Compliance Using ASHRAE 90.1-2019
IESVE Software for Florida Code Compliance Using ASHRAE 90.1-2019
 
Meet the new FSP 3000 M-Flex800™
Meet the new FSP 3000 M-Flex800™Meet the new FSP 3000 M-Flex800™
Meet the new FSP 3000 M-Flex800™
 
Cybersecurity Workshop #1.pptx
Cybersecurity Workshop #1.pptxCybersecurity Workshop #1.pptx
Cybersecurity Workshop #1.pptx
 
20230202 - Introduction to tis-py
20230202 - Introduction to tis-py20230202 - Introduction to tis-py
20230202 - Introduction to tis-py
 
The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...
The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...
The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...
 

Lecture12

  • 1.
  • 2.
  • 3.
  • 4.
  • 5.
  • 6.
  • 7. Ballistic Pendulum H L L L L m M A projectile of mass m moving horizontally with speed v strikes a stationary mass M suspended by strings of length L . Subsequently, m + M rise to a height of H . Given H , M and m what is the initial speed v of the projectile? M + m v V V =0 See I.E. 1 in homework demo Collision Conserves Momentum 0+m v = (M+m) V After, Conserve Energy ½ (M+m) V 2 +0 = 0+(M+m) g H V = sqrt(2 g H) Combine:
  • 8.
  • 9.
  • 10. Explosions ACT “ before” A B Which of these is possible? (Ignore friction and gravity) A B C =both D = Neither “ after” P x = 0 and P y = 0  P x = 0, but  P y > 0  P x = 0, and  P y = 0 M
  • 11.
  • 12. Center of Mass Center of Mass of a system behaves in a SIMPLE way - moves like a point particle ! - velocity of CM is unaffected by collision if F ext = 0 (pork chop demo) P tot = M tot V cm F ext  t =  P tot = M tot  V cm So if F ext  = 0 then V cm is constant Also: F ext = M tot a cm
  • 13.

Editor's Notes

  1. 1
  2. 1
  3. Define Elastic, Inelastic and totally inelastic
  4. Lots of people think inelastic means 0 KE at end.
  5. Transparency. Note that H = ½ L (x/L)^2 useful since we measure x not H.