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Acceleration and constant speed question

  • Thread starter dbzsongoku
  • Start date
Can someone tell me which of the these is true or false and possibly explain it to me?

a)The acceleration of a car is zero when it is turning right at a constant speed
b)The acceleration of a car is zero when it is driving up a long straight incline at constant speed
c)The acceleration of a car is zero when it is topping the crest of a hill at constant speed
d)The acceleration of a car is zero when it is bottoming out at the lowest point of a valley at constant speed
e) The acceleration of a car is zero when it is speeding up as it descends a long straight decline.

Any help would be great.

thanks
 

Answers and Replies

dextercioby
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What are your answers/hunches and the reasoning behind them...??

Daniel.

P.S.Read the "sticky" at the top of the thread...
 
DB
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These are fairly easy questions if you just Think. Consider acceleration as the rate of change in speed, in your case ou can even think of it as a change in speed. Think of forces dependent on inclinations.
 
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Make sure you know exactly what acceleration is. In order for an object to accelerate, its velocity must be changing.
 
dextercioby
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THE VELOCITY VECTOR MUST BE CHANGING WITH TIME AS TO HAVE A NONZERO ACCELERATION VECTOR...

Daniel.
 
Is this correct?
a) false because direction is changing
b) true
c) true
d) true
e) false because magnitude of the accerlation is changing
 
dextercioby
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The way i see it,only B is true...

Daniel.
 
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dbzsongoku said:
Is this correct?
a) false because direction is changing
b) true
c) true
d) true
e) false because magnitude of the accerlation is changing
why does your argment for a not apply to c and d?
 
HallsofIvy
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DB said:
These are fairly easy questions if you just Think. Consider acceleration as the rate of change in speed, in your case ou can even think of it as a change in speed. Think of forces dependent on inclinations.
Unfortunately, thinking THAT way will lead you to the wrong answer to at least one of these. Think "velocity" not "speed"!
 

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