Re: Car acceleration

[Chris Horton <ChrisAHorton2@HOTMAIL.COM>]

One could argue that E is the correct answer: The force of the foot on the
pedal causes a chain of events with the result that the car accelerates.

No, I am not just being facetious.  The joker in this deck is the word
"causes".  This word as commonly used (and I don't remember it being
redefined in any physics curriculum) does not preclude any number of
intermediate agencies, time delays, etc.

A better wording might be "What force acts on the car to accelerate it
forward?"
Chris

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Christopher A. Horton, Ph.D.
4158 RR#3 (Hwy. 204)
Amherst, NS B4H 3Y1
CANADA
ChrisAHorton2@hotmail.com
(902) 447-2109

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"Many discoveries are reserved for ages still to come, when memory of us
will have been effaced.  Our universe is a sorry little affair unless it has
in it something for every age to investigate ... Nature does not reveal her
mysteries once and for all."
- Seneca, "Natural Questions", first century, quoted by Carl Sagan in
"Cosmos", p.xi.

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----- Original Message -----
From: Gary Turner <turner@MORNINGSIDE.EDU>
To: <PHYS-L@lists.nau.edu>
Sent: Friday, February 01, 2002 7:11 PM
Subject: Car acceleration


> I came across this question in an FCI-type set of questions:
>
> A car accelerates forward from a stop sign.  Air resistance slows the
> motion.  What force causes the car to accelerate forward?
> A) It's weight
> B) The force of the engine on the tires
> C) The friction on the car from the road
> D) The upward force exerted on the car by the road
> E) The force of the driver on the accelerator pedal
>
> When I first read this, I thought I got the answer (which was the
'correct'
> answer).  That is below.  Then I thought about it some more from an energy
> standpoint - now I'm not so sure.  What does the group think?
>
>
>
>
>
>
>
>
> Answer: C