Car Acceleration questions

1. Oct 13, 2008

aquapod17

1. The problem statement, all variables and given/known data

Which of the following is true?
a. None of these answers are correct.
b. If a car is traveling eastward, its acceleration is eastward.
c. A particle with constant acceleration can never stop and stay stopped.
d. If a car is slowing down, its acceleration must be negative.

2. Relevant equations
a = v/t

3. The attempt at a solution
I'm not sure what the answer is. I'm thinking it's a, but I'm not really sure.

2. Oct 13, 2008

nicksauce

For a let's try to think of a simple analogy.
a) If a man is jumping upward, his acceleration is upward.
Can you see why this isn't true?

b) A little ambiguous, but can you think of a way a particle can have a constant acceleration, and not be moving?

c) Again, a little ambiguous... but I just picture everything here going in the positive x direction. Just think about how velocity and acceleration relate. acceleration = change in speed divided by change in time? If change in speed is negative, what is acceleration?

3. Oct 13, 2008

tornzaer

I'd say it's "d". Slowing down is pretty much negative acceleration.

b: The car might be going east, but it might be traveling at a constant velocity.
c: Outside force to stop it.

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