(c) What is the acceleration 
of car P relative to Barbara during the braking?
of car P relative to Barbara during the braking? | |
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| KEY IDEAS | |
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Calculation: We know the initial velocity of P relative to Barbara from part (a) 
. The final velocity of P relative to Barbara is −52 km/h (this is the velocity of the stopped car relative to the moving Barbara). Thus,
Comment: We should have foreseen this result: Because Alex and Barbara have a constant relative velocity, they must measure the same acceleration for the car.
. The final velocity of P relative to Barbara is −52 km/h (this is the velocity of the stopped car relative to the moving Barbara). Thus,
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| (Answer) |
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