[SPLIT] displacement: s(t) = -t^2 + 6t + 14, x not equal to

[hank]

I had a question on a test today which was to find the displacement of a particle and the average velocity of a particle using the formula:

s(t) = -t^2 + 6x + 14
x not = 2, x sub1 = 5

what I did to find the displacement was to take s(5) - s(2) which = -3.

Then to find the average velocity I did displacement / time, or (s(5) - s(2)) / (5-2) = -1.

Where did I make my mistake?

 

[stapel]

How does x relate to t and/or s? Over what interval were you to find the average? On what basis do you feel the answer you turned in was incorrect?

Thank you.

Eliz.