22
CHAPTER 3 SECTION 3 Energy and Work: Why Air Bags?
CHAPTER 3 SECTION 3Energy and Work Why Air Bags
PHYSICS 33 ENERGY AND WORKHOMEWORK 1-10 SKIP 4 AND 7 DUE FRIDAY Learning Objective
Students will be able to describe the relationship between stopping distance and force required to stop an object
Success Criteria Model an automobile
air bag Relate W=FD to the
eggsperiment (get it)
Do Now QUIZ
Agenda Do Now Investigate 33 SummaryExit Ticket
EGG LAB Dropping Eggs Throwing an egg in a blanket
EXIT TICKET How did the indentation of the egg in the
flour change as you increased the initial drop height
PHYSICS TALK 33 Learning Objective
Students will be able to explain the relationship between work and kinetic energy
Success Criteria Students will be able to
explain the relationship between stopping distance and force required to stop
Students will be able to explain the relationship between velocity and braking distance
Students will describe which features of a car help in the case of a collision
Do Now WDYSWDYT p 277
Agenda Do Now Physics Talk 33 What do you think
now Summary
PHYSICS TALK 33 What is kinetic
energy
What is the equation
The energy an object has because of its motion
2
21 mvKE
KINETIC ENERGY AND THE EGGS The two eggs were
dropped from the same height Which had more kinetic energy
Since both eggs had approximately the same mass and same relative velocity they about the same kinetic energy
MEASURING FORCE OVER A DISTANCE How was the egg
able to stop
How do you measure the distance in each egg drop
The surface had to apply a force over some distance
When the egg was dropped in flour you can measure the indentation With the hard surface you cannot see the indentation
BRAKING A CAR How do auto brakes
work The braking system
has to eliminate the kinetic energy of the vehicle by applying a large force over a large distance
WORK How do you
calculate work
How does work relate to kinetic energy
W=FD
Work is the change in kinetic energy We can write this as
KEW
BRAKING A CAR
EXAMPLE
WHAT ABOUT THE EGGS How does this apply
to the eggs When the egg could
be stopped over a greater distance there was less damage to it because less force had to be applied
How does this apply to a car crash
Airbags These allow you to have more distance to stop your body so you will be less likely to get hurt
If you are traveling three-times the speed will you need three times the braking distance
False You will need 9 times the stopping distance This is because in the formula the velocity is squared
2
21 mvKE
Why is it harder to stop on icy or wet roads
The slippery surface makes it more difficult to supply a sufficient force so it is necessary to give yourself more distance
What else helps stop an automobile
The crumple zone of a car allows the car to have more distance to stop This is why cars are designed to dent and are not made out of more sturdy material
SAMPLE PROBLEM p286 and 287 Sample Problem
WHAT DO YOU THINK NOWExit Ticket How does and air bag protect you
during an accident
PHYSICS 33 ENERGY AND WORKHOMEWORK 1-10 SKIP 4 AND 7 DUE FRIDAY Learning Objective
Students will be able to describe the relationship between stopping distance and force required to stop an object
Success Criteria Model an automobile
air bag Relate W=FD to the
eggsperiment (get it)
Do Now QUIZ
Agenda Do Now Investigate 33 SummaryExit Ticket
EGG LAB Dropping Eggs Throwing an egg in a blanket
EXIT TICKET How did the indentation of the egg in the
flour change as you increased the initial drop height
PHYSICS TALK 33 Learning Objective
Students will be able to explain the relationship between work and kinetic energy
Success Criteria Students will be able to
explain the relationship between stopping distance and force required to stop
Students will be able to explain the relationship between velocity and braking distance
Students will describe which features of a car help in the case of a collision
Do Now WDYSWDYT p 277
Agenda Do Now Physics Talk 33 What do you think
now Summary
PHYSICS TALK 33 What is kinetic
energy
What is the equation
The energy an object has because of its motion
2
21 mvKE
KINETIC ENERGY AND THE EGGS The two eggs were
dropped from the same height Which had more kinetic energy
Since both eggs had approximately the same mass and same relative velocity they about the same kinetic energy
MEASURING FORCE OVER A DISTANCE How was the egg
able to stop
How do you measure the distance in each egg drop
The surface had to apply a force over some distance
When the egg was dropped in flour you can measure the indentation With the hard surface you cannot see the indentation
BRAKING A CAR How do auto brakes
work The braking system
has to eliminate the kinetic energy of the vehicle by applying a large force over a large distance
WORK How do you
calculate work
How does work relate to kinetic energy
W=FD
Work is the change in kinetic energy We can write this as
KEW
BRAKING A CAR
EXAMPLE
WHAT ABOUT THE EGGS How does this apply
to the eggs When the egg could
be stopped over a greater distance there was less damage to it because less force had to be applied
How does this apply to a car crash
Airbags These allow you to have more distance to stop your body so you will be less likely to get hurt
If you are traveling three-times the speed will you need three times the braking distance
False You will need 9 times the stopping distance This is because in the formula the velocity is squared
2
21 mvKE
Why is it harder to stop on icy or wet roads
The slippery surface makes it more difficult to supply a sufficient force so it is necessary to give yourself more distance
What else helps stop an automobile
The crumple zone of a car allows the car to have more distance to stop This is why cars are designed to dent and are not made out of more sturdy material
SAMPLE PROBLEM p286 and 287 Sample Problem
WHAT DO YOU THINK NOWExit Ticket How does and air bag protect you
during an accident
EGG LAB Dropping Eggs Throwing an egg in a blanket
EXIT TICKET How did the indentation of the egg in the
flour change as you increased the initial drop height
PHYSICS TALK 33 Learning Objective
Students will be able to explain the relationship between work and kinetic energy
Success Criteria Students will be able to
explain the relationship between stopping distance and force required to stop
Students will be able to explain the relationship between velocity and braking distance
Students will describe which features of a car help in the case of a collision
Do Now WDYSWDYT p 277
Agenda Do Now Physics Talk 33 What do you think
now Summary
PHYSICS TALK 33 What is kinetic
energy
What is the equation
The energy an object has because of its motion
2
21 mvKE
KINETIC ENERGY AND THE EGGS The two eggs were
dropped from the same height Which had more kinetic energy
Since both eggs had approximately the same mass and same relative velocity they about the same kinetic energy
MEASURING FORCE OVER A DISTANCE How was the egg
able to stop
How do you measure the distance in each egg drop
The surface had to apply a force over some distance
When the egg was dropped in flour you can measure the indentation With the hard surface you cannot see the indentation
BRAKING A CAR How do auto brakes
work The braking system
has to eliminate the kinetic energy of the vehicle by applying a large force over a large distance
WORK How do you
calculate work
How does work relate to kinetic energy
W=FD
Work is the change in kinetic energy We can write this as
KEW
BRAKING A CAR
EXAMPLE
WHAT ABOUT THE EGGS How does this apply
to the eggs When the egg could
be stopped over a greater distance there was less damage to it because less force had to be applied
How does this apply to a car crash
Airbags These allow you to have more distance to stop your body so you will be less likely to get hurt
If you are traveling three-times the speed will you need three times the braking distance
False You will need 9 times the stopping distance This is because in the formula the velocity is squared
2
21 mvKE
Why is it harder to stop on icy or wet roads
The slippery surface makes it more difficult to supply a sufficient force so it is necessary to give yourself more distance
What else helps stop an automobile
The crumple zone of a car allows the car to have more distance to stop This is why cars are designed to dent and are not made out of more sturdy material
SAMPLE PROBLEM p286 and 287 Sample Problem
WHAT DO YOU THINK NOWExit Ticket How does and air bag protect you
during an accident
EXIT TICKET How did the indentation of the egg in the
flour change as you increased the initial drop height
PHYSICS TALK 33 Learning Objective
Students will be able to explain the relationship between work and kinetic energy
Success Criteria Students will be able to
explain the relationship between stopping distance and force required to stop
Students will be able to explain the relationship between velocity and braking distance
Students will describe which features of a car help in the case of a collision
Do Now WDYSWDYT p 277
Agenda Do Now Physics Talk 33 What do you think
now Summary
PHYSICS TALK 33 What is kinetic
energy
What is the equation
The energy an object has because of its motion
2
21 mvKE
KINETIC ENERGY AND THE EGGS The two eggs were
dropped from the same height Which had more kinetic energy
Since both eggs had approximately the same mass and same relative velocity they about the same kinetic energy
MEASURING FORCE OVER A DISTANCE How was the egg
able to stop
How do you measure the distance in each egg drop
The surface had to apply a force over some distance
When the egg was dropped in flour you can measure the indentation With the hard surface you cannot see the indentation
BRAKING A CAR How do auto brakes
work The braking system
has to eliminate the kinetic energy of the vehicle by applying a large force over a large distance
WORK How do you
calculate work
How does work relate to kinetic energy
W=FD
Work is the change in kinetic energy We can write this as
KEW
BRAKING A CAR
EXAMPLE
WHAT ABOUT THE EGGS How does this apply
to the eggs When the egg could
be stopped over a greater distance there was less damage to it because less force had to be applied
How does this apply to a car crash
Airbags These allow you to have more distance to stop your body so you will be less likely to get hurt
If you are traveling three-times the speed will you need three times the braking distance
False You will need 9 times the stopping distance This is because in the formula the velocity is squared
2
21 mvKE
Why is it harder to stop on icy or wet roads
The slippery surface makes it more difficult to supply a sufficient force so it is necessary to give yourself more distance
What else helps stop an automobile
The crumple zone of a car allows the car to have more distance to stop This is why cars are designed to dent and are not made out of more sturdy material
SAMPLE PROBLEM p286 and 287 Sample Problem
WHAT DO YOU THINK NOWExit Ticket How does and air bag protect you
during an accident
PHYSICS TALK 33 Learning Objective
Students will be able to explain the relationship between work and kinetic energy
Success Criteria Students will be able to
explain the relationship between stopping distance and force required to stop
Students will be able to explain the relationship between velocity and braking distance
Students will describe which features of a car help in the case of a collision
Do Now WDYSWDYT p 277
Agenda Do Now Physics Talk 33 What do you think
now Summary
PHYSICS TALK 33 What is kinetic
energy
What is the equation
The energy an object has because of its motion
2
21 mvKE
KINETIC ENERGY AND THE EGGS The two eggs were
dropped from the same height Which had more kinetic energy
Since both eggs had approximately the same mass and same relative velocity they about the same kinetic energy
MEASURING FORCE OVER A DISTANCE How was the egg
able to stop
How do you measure the distance in each egg drop
The surface had to apply a force over some distance
When the egg was dropped in flour you can measure the indentation With the hard surface you cannot see the indentation
BRAKING A CAR How do auto brakes
work The braking system
has to eliminate the kinetic energy of the vehicle by applying a large force over a large distance
WORK How do you
calculate work
How does work relate to kinetic energy
W=FD
Work is the change in kinetic energy We can write this as
KEW
BRAKING A CAR
EXAMPLE
WHAT ABOUT THE EGGS How does this apply
to the eggs When the egg could
be stopped over a greater distance there was less damage to it because less force had to be applied
How does this apply to a car crash
Airbags These allow you to have more distance to stop your body so you will be less likely to get hurt
If you are traveling three-times the speed will you need three times the braking distance
False You will need 9 times the stopping distance This is because in the formula the velocity is squared
2
21 mvKE
Why is it harder to stop on icy or wet roads
The slippery surface makes it more difficult to supply a sufficient force so it is necessary to give yourself more distance
What else helps stop an automobile
The crumple zone of a car allows the car to have more distance to stop This is why cars are designed to dent and are not made out of more sturdy material
SAMPLE PROBLEM p286 and 287 Sample Problem
WHAT DO YOU THINK NOWExit Ticket How does and air bag protect you
during an accident
PHYSICS TALK 33 What is kinetic
energy
What is the equation
The energy an object has because of its motion
2
21 mvKE
KINETIC ENERGY AND THE EGGS The two eggs were
dropped from the same height Which had more kinetic energy
Since both eggs had approximately the same mass and same relative velocity they about the same kinetic energy
MEASURING FORCE OVER A DISTANCE How was the egg
able to stop
How do you measure the distance in each egg drop
The surface had to apply a force over some distance
When the egg was dropped in flour you can measure the indentation With the hard surface you cannot see the indentation
BRAKING A CAR How do auto brakes
work The braking system
has to eliminate the kinetic energy of the vehicle by applying a large force over a large distance
WORK How do you
calculate work
How does work relate to kinetic energy
W=FD
Work is the change in kinetic energy We can write this as
KEW
BRAKING A CAR
EXAMPLE
WHAT ABOUT THE EGGS How does this apply
to the eggs When the egg could
be stopped over a greater distance there was less damage to it because less force had to be applied
How does this apply to a car crash
Airbags These allow you to have more distance to stop your body so you will be less likely to get hurt
If you are traveling three-times the speed will you need three times the braking distance
False You will need 9 times the stopping distance This is because in the formula the velocity is squared
2
21 mvKE
Why is it harder to stop on icy or wet roads
The slippery surface makes it more difficult to supply a sufficient force so it is necessary to give yourself more distance
What else helps stop an automobile
The crumple zone of a car allows the car to have more distance to stop This is why cars are designed to dent and are not made out of more sturdy material
SAMPLE PROBLEM p286 and 287 Sample Problem
WHAT DO YOU THINK NOWExit Ticket How does and air bag protect you
during an accident
KINETIC ENERGY AND THE EGGS The two eggs were
dropped from the same height Which had more kinetic energy
Since both eggs had approximately the same mass and same relative velocity they about the same kinetic energy
MEASURING FORCE OVER A DISTANCE How was the egg
able to stop
How do you measure the distance in each egg drop
The surface had to apply a force over some distance
When the egg was dropped in flour you can measure the indentation With the hard surface you cannot see the indentation
BRAKING A CAR How do auto brakes
work The braking system
has to eliminate the kinetic energy of the vehicle by applying a large force over a large distance
WORK How do you
calculate work
How does work relate to kinetic energy
W=FD
Work is the change in kinetic energy We can write this as
KEW
BRAKING A CAR
EXAMPLE
WHAT ABOUT THE EGGS How does this apply
to the eggs When the egg could
be stopped over a greater distance there was less damage to it because less force had to be applied
How does this apply to a car crash
Airbags These allow you to have more distance to stop your body so you will be less likely to get hurt
If you are traveling three-times the speed will you need three times the braking distance
False You will need 9 times the stopping distance This is because in the formula the velocity is squared
2
21 mvKE
Why is it harder to stop on icy or wet roads
The slippery surface makes it more difficult to supply a sufficient force so it is necessary to give yourself more distance
What else helps stop an automobile
The crumple zone of a car allows the car to have more distance to stop This is why cars are designed to dent and are not made out of more sturdy material
SAMPLE PROBLEM p286 and 287 Sample Problem
WHAT DO YOU THINK NOWExit Ticket How does and air bag protect you
during an accident
MEASURING FORCE OVER A DISTANCE How was the egg
able to stop
How do you measure the distance in each egg drop
The surface had to apply a force over some distance
When the egg was dropped in flour you can measure the indentation With the hard surface you cannot see the indentation
BRAKING A CAR How do auto brakes
work The braking system
has to eliminate the kinetic energy of the vehicle by applying a large force over a large distance
WORK How do you
calculate work
How does work relate to kinetic energy
W=FD
Work is the change in kinetic energy We can write this as
KEW
BRAKING A CAR
EXAMPLE
WHAT ABOUT THE EGGS How does this apply
to the eggs When the egg could
be stopped over a greater distance there was less damage to it because less force had to be applied
How does this apply to a car crash
Airbags These allow you to have more distance to stop your body so you will be less likely to get hurt
If you are traveling three-times the speed will you need three times the braking distance
False You will need 9 times the stopping distance This is because in the formula the velocity is squared
2
21 mvKE
Why is it harder to stop on icy or wet roads
The slippery surface makes it more difficult to supply a sufficient force so it is necessary to give yourself more distance
What else helps stop an automobile
The crumple zone of a car allows the car to have more distance to stop This is why cars are designed to dent and are not made out of more sturdy material
SAMPLE PROBLEM p286 and 287 Sample Problem
WHAT DO YOU THINK NOWExit Ticket How does and air bag protect you
during an accident
BRAKING A CAR How do auto brakes
work The braking system
has to eliminate the kinetic energy of the vehicle by applying a large force over a large distance
WORK How do you
calculate work
How does work relate to kinetic energy
W=FD
Work is the change in kinetic energy We can write this as
KEW
BRAKING A CAR
EXAMPLE
WHAT ABOUT THE EGGS How does this apply
to the eggs When the egg could
be stopped over a greater distance there was less damage to it because less force had to be applied
How does this apply to a car crash
Airbags These allow you to have more distance to stop your body so you will be less likely to get hurt
If you are traveling three-times the speed will you need three times the braking distance
False You will need 9 times the stopping distance This is because in the formula the velocity is squared
2
21 mvKE
Why is it harder to stop on icy or wet roads
The slippery surface makes it more difficult to supply a sufficient force so it is necessary to give yourself more distance
What else helps stop an automobile
The crumple zone of a car allows the car to have more distance to stop This is why cars are designed to dent and are not made out of more sturdy material
SAMPLE PROBLEM p286 and 287 Sample Problem
WHAT DO YOU THINK NOWExit Ticket How does and air bag protect you
during an accident
WORK How do you
calculate work
How does work relate to kinetic energy
W=FD
Work is the change in kinetic energy We can write this as
KEW
BRAKING A CAR
EXAMPLE
WHAT ABOUT THE EGGS How does this apply
to the eggs When the egg could
be stopped over a greater distance there was less damage to it because less force had to be applied
How does this apply to a car crash
Airbags These allow you to have more distance to stop your body so you will be less likely to get hurt
If you are traveling three-times the speed will you need three times the braking distance
False You will need 9 times the stopping distance This is because in the formula the velocity is squared
2
21 mvKE
Why is it harder to stop on icy or wet roads
The slippery surface makes it more difficult to supply a sufficient force so it is necessary to give yourself more distance
What else helps stop an automobile
The crumple zone of a car allows the car to have more distance to stop This is why cars are designed to dent and are not made out of more sturdy material
SAMPLE PROBLEM p286 and 287 Sample Problem
WHAT DO YOU THINK NOWExit Ticket How does and air bag protect you
during an accident
BRAKING A CAR
EXAMPLE
WHAT ABOUT THE EGGS How does this apply
to the eggs When the egg could
be stopped over a greater distance there was less damage to it because less force had to be applied
How does this apply to a car crash
Airbags These allow you to have more distance to stop your body so you will be less likely to get hurt
If you are traveling three-times the speed will you need three times the braking distance
False You will need 9 times the stopping distance This is because in the formula the velocity is squared
2
21 mvKE
Why is it harder to stop on icy or wet roads
The slippery surface makes it more difficult to supply a sufficient force so it is necessary to give yourself more distance
What else helps stop an automobile
The crumple zone of a car allows the car to have more distance to stop This is why cars are designed to dent and are not made out of more sturdy material
SAMPLE PROBLEM p286 and 287 Sample Problem
WHAT DO YOU THINK NOWExit Ticket How does and air bag protect you
during an accident
EXAMPLE
WHAT ABOUT THE EGGS How does this apply
to the eggs When the egg could
be stopped over a greater distance there was less damage to it because less force had to be applied
How does this apply to a car crash
Airbags These allow you to have more distance to stop your body so you will be less likely to get hurt
If you are traveling three-times the speed will you need three times the braking distance
False You will need 9 times the stopping distance This is because in the formula the velocity is squared
2
21 mvKE
Why is it harder to stop on icy or wet roads
The slippery surface makes it more difficult to supply a sufficient force so it is necessary to give yourself more distance
What else helps stop an automobile
The crumple zone of a car allows the car to have more distance to stop This is why cars are designed to dent and are not made out of more sturdy material
SAMPLE PROBLEM p286 and 287 Sample Problem
WHAT DO YOU THINK NOWExit Ticket How does and air bag protect you
during an accident
WHAT ABOUT THE EGGS How does this apply
to the eggs When the egg could
be stopped over a greater distance there was less damage to it because less force had to be applied
How does this apply to a car crash
Airbags These allow you to have more distance to stop your body so you will be less likely to get hurt
If you are traveling three-times the speed will you need three times the braking distance
False You will need 9 times the stopping distance This is because in the formula the velocity is squared
2
21 mvKE
Why is it harder to stop on icy or wet roads
The slippery surface makes it more difficult to supply a sufficient force so it is necessary to give yourself more distance
What else helps stop an automobile
The crumple zone of a car allows the car to have more distance to stop This is why cars are designed to dent and are not made out of more sturdy material
SAMPLE PROBLEM p286 and 287 Sample Problem
WHAT DO YOU THINK NOWExit Ticket How does and air bag protect you
during an accident
How does this apply to a car crash
Airbags These allow you to have more distance to stop your body so you will be less likely to get hurt
If you are traveling three-times the speed will you need three times the braking distance
False You will need 9 times the stopping distance This is because in the formula the velocity is squared
2
21 mvKE
Why is it harder to stop on icy or wet roads
The slippery surface makes it more difficult to supply a sufficient force so it is necessary to give yourself more distance
What else helps stop an automobile
The crumple zone of a car allows the car to have more distance to stop This is why cars are designed to dent and are not made out of more sturdy material
SAMPLE PROBLEM p286 and 287 Sample Problem
WHAT DO YOU THINK NOWExit Ticket How does and air bag protect you
during an accident
If you are traveling three-times the speed will you need three times the braking distance
False You will need 9 times the stopping distance This is because in the formula the velocity is squared
2
21 mvKE
Why is it harder to stop on icy or wet roads
The slippery surface makes it more difficult to supply a sufficient force so it is necessary to give yourself more distance
What else helps stop an automobile
The crumple zone of a car allows the car to have more distance to stop This is why cars are designed to dent and are not made out of more sturdy material
SAMPLE PROBLEM p286 and 287 Sample Problem
WHAT DO YOU THINK NOWExit Ticket How does and air bag protect you
during an accident
Why is it harder to stop on icy or wet roads
The slippery surface makes it more difficult to supply a sufficient force so it is necessary to give yourself more distance
What else helps stop an automobile
The crumple zone of a car allows the car to have more distance to stop This is why cars are designed to dent and are not made out of more sturdy material
SAMPLE PROBLEM p286 and 287 Sample Problem
WHAT DO YOU THINK NOWExit Ticket How does and air bag protect you
during an accident
What else helps stop an automobile
The crumple zone of a car allows the car to have more distance to stop This is why cars are designed to dent and are not made out of more sturdy material
SAMPLE PROBLEM p286 and 287 Sample Problem
WHAT DO YOU THINK NOWExit Ticket How does and air bag protect you
during an accident
SAMPLE PROBLEM p286 and 287 Sample Problem
WHAT DO YOU THINK NOWExit Ticket How does and air bag protect you
during an accident
WHAT DO YOU THINK NOWExit Ticket How does and air bag protect you
during an accident
