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Homework Statement
At t= 0s a truck is stopped at a traffic light. When the light turns green, the truck starts to speed up, and gains speed at a constant rate until it reaches a speed of 20m/s 8 seconds after the light turns green. The truck continues at a constant speed for 60m . Then the truck driver sees a red light up ahead at the next intersection, and starts slowing down at a constant rate. The truck stops at the red light, 180m from where it was at .
Draw accurate graph for the motion of the truck.
Homework Equations
x-x_0 = t.2(v initial + v final)
The Attempt at a Solution
I would think that the line is linear, since as time passes by the distance away from origing keeps on increasing.
But the problem states that it speeds up until it reaches constant speed of 20m/s.
So for the first 8 seconds, the speed will increase until it reaches 20m/s.
That is the problem I have having in starting.
I would use the equation listed above, but
x final = ?
x initital = 0
t= 1 (this number varies, as I plot points throughout)
v initial = 0
v final = ? (I would not know how this would work, as I know that velocity would be 20m/s at 8seconds, before it must be increasing)
and
a = ? (unknown to me)
How would I approach this problem.
What I've done thusfar.
http://img259.imageshack.us/img259/1096/untitledgi9.jpg
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