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I'm having trouble understanding this frame of reference question.

You are traveling in a car going at a constant speed of 100 km/hr down a long, straight highway. You pass another car going in the same direction which is traveling at a constant speed of 80 km/hr. As measured from your car’s reference frame this other car is traveling at -20 km/hr. What is the acceleration of your car as measured from the other car’s reference frame? What is the acceleration of the other car as measured from your car’s reference frame?

Shouldn't they both appear to have an acceleration of zero, because both velocities are constant? I can imagine sitting in the faster car and watching the slower car, its speed would not appear to change, only its position?


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up vote 1 down vote accepted

Yes. Acceleration is zero. Note the word constant used to describe both speeds.

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So in both frames of reference, the acceleration should appear to be zero? I feel like this question is a trick question. – csnate Sep 24 '13 at 1:27
I feel it too, but maybe they just think they are being tricky by wording it that way. The facts are the facts. You did not accelerate, the other car did not accelerate. Your observation is that he is moving with a constant velocity of -20 (Given). His observation is that you are moving with a constant velocity of +20. – John Faulkner Sep 24 '13 at 1:37

protected by Qmechanic Nov 6 '13 at 0:47

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