Finding Acceleration

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staceyrho

Junior Member
Joined
Jan 12, 2007
Messages
76
Okay I have a question I believe I'm doing correct but getting the wrong answer.

Question:
Consider the plot below describing the velocity of a car along a straight line with an inital position of 0 m and an initial velocity of 0 m/s.

What is the acceleration at 7s? Answer in units of m/s^2

I can't past the chart in here but at 7s tge velocity is at -16 m/s.

The formula i'm using is a= v/t.
 
Posting your work so we can see what you have done would be better next time.

However,

**Edit** Vector symbols don't seem to show up for me, so I left them out - Make sure you include them.

\(\displaystyle \[
\begin{array}{l}
a\; = \;\frac{v}{t} \\
a\; = \;\frac{{ - 16\;m/s\; - \;0\;m/s}}{{7\;s\; - \;0\;s}} \\
a\; = \;\frac{{ - 16\;m/s}}{{7\;s}} \\
a\; = \; - 2.2857...\;m/s^2 \\
\end{array}
\]\)

It is decelerating at 2.2857 m/s^2.

Since I am not given the complete question I have left a bunch of digits on the final answer. You should make sure you keep the right number of significant digits.
 
I tried to put the graff on here but I couldn't figure out how to do that. But that's the same answer I got and my homework site say's that's the wrong answer.
 
the instantaneous acceleration will be the slope of the velocity graph at the point (7, -16).
 
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