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Acceleration straight line graph

  • #1

Homework Statement


A particle starts from rest and accelerates as shown in the attached figure. Determine (a) the article's speed at t=10s and t=20s. (b) The distance traveled in the first 20s.


Homework Equations



a=dv/dt

The Attempt at a Solution


(a) t=10s, speed = 20m/s
t=20s, speed = 5m/s
Those were obtained by taking the area under the acceleration.

(b) book gives the answer 262m. NO idea how this came about. I thought about 225m being the answer since 20m/s * 10s + 5m/s * 5s, but this wouldn't be correct because the velocity is changing, not constant. Any help would be appreciated.
 

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Answers and Replies

  • #2
265
0
You can use the constant-acceleration equations to work this out.
 
  • #3
k is there a way by the graph or integration? I want to use something that's always going to work, if that's possible.
 
  • #4
SteamKing
Staff Emeritus
Science Advisor
Homework Helper
12,796
1,667
Graphically, the change in velocity from t1 to t2 represents the area under the acceleration curve.

After constructing a velocity curve, the change in displacement is the area under the velocity curve.

If the acceleration curve is positive, how does that affect velocity?
If the acceleration curve is negative, how does that affect velocity?
If the acceleration curve is zero, how does that affect velocity?
 

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