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Constants I Periodic TableBrain injuries in auto accidents. Brain injuriesgenerally occur any time the brain's accelerationreaches 100 g for even a short time. Consider a carrunning into a solid barrier. With an airbag, thedriver's head moves through a distance of 20 cmwhile the airbag stops it. Without anhead continues forward until the seatbelt stops thetorso, causing the head to stop in a distance of only5.0 cm.Part AFind the maximum speed with which the car can strike the barrier withoutcausing brain injury, using anairbagairbag, theExpress your answer to two significant figures and include theappropriate units.?HAValueUnitsRequest AnswerSubmitPart BсаFind the maximum speed with which the car can strike the barrier withoutcausing brain injury, without using an airbagExpress your answer to two significant figures and include theappropriate units.PHA?

Question
Constants I Periodic Table
Brain injuries in auto accidents. Brain injuries
generally occur any time the brain's acceleration
reaches 100 g for even a short time. Consider a car
running into a solid barrier. With an airbag, the
driver's head moves through a distance of 20 cm
while the airbag stops it. Without an
head continues forward until the seatbelt stops the
torso, causing the head to stop in a distance of only
5.0 cm.
Part A
Find the maximum speed with which the car can strike the barrier without
causing brain injury, using an
airbag
airbag, the
Express your answer to two significant figures and include the
appropriate units.
?
HA
Value
Units
Request Answer
Submit
Part B
са
Find the maximum speed with which the car can strike the barrier without
causing brain injury, without using an airbag
Express your answer to two significant figures and include the
appropriate units.
PHA
?
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Constants I Periodic Table Brain injuries in auto accidents. Brain injuries generally occur any time the brain's acceleration reaches 100 g for even a short time. Consider a car running into a solid barrier. With an airbag, the driver's head moves through a distance of 20 cm while the airbag stops it. Without an head continues forward until the seatbelt stops the torso, causing the head to stop in a distance of only 5.0 cm. Part A Find the maximum speed with which the car can strike the barrier without causing brain injury, using an airbag airbag, the Express your answer to two significant figures and include the appropriate units. ? HA Value Units Request Answer Submit Part B са Find the maximum speed with which the car can strike the barrier without causing brain injury, without using an airbag Express your answer to two significant figures and include the appropriate units. PHA ?

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Step 1

Given information:

Brain injuries occur when acceleration (a) reaches: 100g m/s2.

Where g = 9.81 m/s2

Distance travelled by the brain when the air bag is present (S1): 20 cm = 20 × 10-2 m

Distance travelled by the brain when there is no air bag (S2): 5 cm = 5 × 10-2 m

Maximum speed the car can have before hitting the barrier (u):  ?

The final velocity (v) in both the cases: 0 m/s.

From equations of motion we know that

v2 – u2 = 2as

Step 2

Part A: Maximum speed the car can have before hitting the barrier, when the air bag is present:

Substituting the corresponding values in equation of motion mentioned:

v2 – u2 = 2aS1

(0)2 – u2 = 2(-100g) (20 × 10-2 m)

NOTE: - “a” is negative because it is retardation.

We get:

u = 19.8 m/s

Step 3

Part B: Maximum speed the car can have before hitting the barrier, when the air bag is absent:

Substituting the corresponding values in equation of motion mentioned:

v2 &ndas...

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