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Deriving a common formula

  • Thread starter Matt1234
  • Start date
  • #1
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Homework Statement



See the attachment please.


The Attempt at a Solution



I know the v1 x delta (t) is for the rectangle,
I dont see how the second part works? I dont understand why the t^2 and how a replaces the area formula i have written.


Thanks for your help, its my first day of class today, and its been a while since i was last in a physics / math class.

EDIT: I added a formula sheet we were given, sorry i just dont see the relationship right now..
 

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Answers and Replies

  • #2
CompuChip
Science Advisor
Homework Helper
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You can replace [itex]\Delta v = v_2 - v_1[/itex] by the acceleration a. In the picture, the acceleration is the slope of the line, algebraically it is given by
[tex]a = \frac{\Delta v}{\Delta t}[/tex].

So just write down the area of the triangle and do the substitution.
 
  • #3
from the second equation on the formula sheet,
a=[tex]\Delta[/tex]v/[tex]\Delta[/tex]t
a=(vf-vi)/t

from the graph, d=vit+[tex]\frac{1}{2}[/tex](vf-vi)*t
therefore, d=vit+[tex]\frac{1}{2}[/tex]at2
(since vf-vi=at)
 

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