Re: Questions on Neg. and Pos. Acceleration

[Chuck Britton <britton@ODIE.NCSSM.EDU>]

At 7:35 AM -0400 9/23/99, jmanor wrote:
> Is it possible for an object to have a negative acceleration while
> increasing in speed?  And also can you explain if the velocity of an
> object be negative when its acceleration is positive and vice versa?

These questions MUST be covered from a thorough treatment of velocity
vs. time graphs (along with an understanding of such technical words
as

speeding up
slowing down
going forward
going backwards

velocity
!
!      /\
!     /  \
!    /    \
!___/______\____________________ (time)
!  /        \
! /          \
!/            \
!


When you can describe this graph is simple words, you will have the answer.

BTW, I AVOID the acceleration word until we get to Forces. 'Til then
we just describe the velocity changing at a certain rate (slope of
the velocity time graph)

The word acceleration is not necessary and is a MAJOR source of
confusion. It is too easy to 'learn' the acceleration equations
without 'knowing' what's going on.

stress velocity vs. time graphs for understanding AND problem solving.

  -.     .-.     .-.     .-.     .-.     .-.     .-.     .-.     .-.     .-
    \   /   \   /   \ N /   \ C /   \ S /   \ S /   \ M /   \   /   \   /
     `-'     `-'     `-'     `-'     `-'     `-'     `-'     `-'     `-'
Chuck Britton                                   Education is what is left when
britton@odie.ncssm.edu                          you have forgotten everything
North Carolina School of Science & Math         you learned in school.
(919) 286-3366  x224                            Albert Einstein,        1936