Crumple Zones Gizmo Student Exploration: Crumple Zones
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Cours
Physics
Établissement
Physics
Student Exploration: Crumple Zones
Vocabulary: acceleration, airbag, collision avoidance system, crash test dummy, crumple zone,
force, kinetic energy, NeZWon¶s laZs of moWion, safety cell, seat belt, work, work-energy theorem
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
Two bu...
Vocabulary: acceleration, airbag, collision avoidance system, crash test dummy, crumple zone,
force, kinetic energy, Ne on s la s of mo ion, safety cell, seat belt, work, work-energy theorem
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
Two burglars run down an alley at night, trying to escape the cops.
Jack is carrying a rigid metal safe. Jill is carrying an armful of
antique quilts. In the pitch dark, they both collide headlong into a
concrete wall.
1. Who do you think will be hurt more in the collision, and why?
m
er as
behurtmorebecausetherigidsafewillhithimwinthesameforcethatithitsthe
co
Jackwill
eH w
wallbutJill
hasquiltstocushiontheimpact
o.
rs e
ou urc
2. During a car crash, what features of the car might act like either Jack s safe or Jill s q il s?
seamen
ayame
act
carcrashmerigidframewill
Duringa likeJack'ssasewhile theairbagswillactlikeJill'squiltrelieving pressureandimpact
o
aC s
vi y re
Gizmo Warm-up
When cars were first invented, the safety of passengers was
not a great concern. As vehicles grew larger and faster,
ed d
accidents became more deadly. Safety features went from
ar stu
being a rare luxury to a legal requirement. In the Crumple
Zones Gizmo, you will design cars that will help a crash test
dummy survive a collision.
sh is
1. To begin, do not make any changes to the DESIGN tab of the Gizmo. Select the CRASH
Th
TEST tab, and click Play ( ). After the crash, click Slo-mo replay. What happens?
Thecar crashes into a concrete wall and pieces of glass flyoff the windshield
2. Select the RESULTS tab to read about the results of the crash. Do you think a passenger
A passenger wouldn't be able
would have survived this car crash? Explain.
to survive this crash because of trauma to the headandtorso
This study source was downloaded by 100000826192319 from CourseHero.com on 09-13-2021 05:13:47 GMT -05:00
2019
, Get the Gizmo ready:
Activity A:
Click Reset ( ).
Surviving a crash
On the DESIGN tab, check that Sedan is selected.
Introduction: Modern vehicles contain features designed to keep passengers safe in a crash.
The crumple zone in the front of the car slows the car gradually and increases stopping time.
The safety cell is a rigid cage that prevents passengers from being crushed. Inside, seat belts
and airbags prevent the driver from hitting the windshield, steering wheel, or dashboard.
Question: How does a crumple zone help protect a passenger?
1. Make a hypothesis: On the DESIGN tab, look at the parameters you can control. What
settings do you think will make the safest car? Set up the Gizmo, and then fill in below.
Crumple zone length: 120cm Crumple zone rigidity: 2750kW Safety cell rigidity: 1000kW
Seat belt present? yes If present, seat belt stiffness:
m
48 KMm
er as
Air bag present?Yes If present, air bag rigidity: 5 kN
co
eH w
o.
2. Test: On the CRASH TEST tab, check that the Car 1 speed is 16 m/s, or about 35 miles per
rs e
hour (mph). Click Play. After the crash, select the RESULTS tab.
ou urc
A. By what percentage did the crumple zone deform? 0.07M Safety cell? 0.19
o
B. Did the dummy hit the steering wheel? No
aC s
C. What was the maximum force on the dummy? 27.88kW
vi y re
D. How likely was the dummy to survive? 701
In this simulation, forces are measured in kilonewtons (kN). One kilonewton is equal to 1000
ed d
newtons, or the force of a 225-pound (102 kg) person standing on your chest. While many
ar stu
factors affect survival, only the maximum force and safety cell collapse are considered here.
3. Experiment: On the DESIGN tab, set the Crumple zone length to 100 cm and the Safety
sh is
cell rigidity to 2000 kN. Set the Seat belt stiffness to 50 kN/m and turn off the Airbag. For
each Crumple zone rigidity setting, run a 16 m/s crash test and enter the results below.
Th
Crumple zone Crumple zone Dummy Max. force on Likelihood of
rigidity deformation displacement dummy survival
100 kN
Im 1.42M 20.88kW 871
200 kN 1.21M 14.25kW loot
0.93M
300 kN 0.93M 1.22M 14.7kW 99
400 kN 0.93M 1.23M 14.93kW 99
(Activity A continued on next page)
This study source was downloaded by 100000826192319 from CourseHero.com on 09-13-2021 05:13:47 GMT -05:00
2019
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