# Thread: Displacement (net change)

1. ## Displacement (net change)

The velocity function is v(t)= -t^2 +4t -3 for a particle moving along a line. Find the displacement (net distance covered) of the particle during the time interval [-1,6].

I've tried integrating the function and then plugging in the values.
Also I tried factorizing the function and dividing the integral based on the negative and positive sign and then integrating and plugging the values.

But none of the methods give the right answer. Anybody got other ideas?

2. Don't leave us hanging man! What is the right answer?

3. Originally Posted by maddas
Don't leave us hanging man! What is the right answer?
I have no idea!!!! I gotta solve this question for an assignment that I have to submit tomorrow and I'm really stuck!

4. Originally Posted by mag6
The velocity function is v(t)= -t^2 +4t -3 for a particle moving along a line. Find the displacement (net distance covered) of the particle during the time interval [-1,6].

I've tried integrating the function and then plugging in the values.
Also I tried factorizing the function and dividing the integral based on the negative and positive sign and then integrating and plugging the values.

But none of the methods give the right answer. Anybody got other ideas?
Have you tried integrating the velocity to find displacement as a function of time without bounds.

5. If you don't know the right answer, how do you know that the integral of v from -1 to 6 is wrong?

6. Originally Posted by AllanCuz
Have you tried integrating the velocity to find displacement as a function of time. Then plug in d(6) + d(-1)?
yea....I did that....the answer ws 70/3 or something. But that's not working

7. Originally Posted by maddas
If you don't know the right answer, how do you know that the integral of v from -1 to 6 is wrong?
Its an online assignment. So when you submit an answer it tells you immediately if its rite or wrong....

8. Originally Posted by mag6
yea....I did that....the answer ws 70/3 or something. But that's not working
Yes I know. I'm slightly tired right now lol.

What does the integral of the velocity equation represent?

9. Originally Posted by AllanCuz
Yes I know. I'm slightly tired right now lol.

What does the integral of the velocity equation represent?
the v(t) is the velocity at time t and the integral would be the net distance covered by the particle in time t.....i guess!

10. +70/3 or -70/3?

11. Originally Posted by maddas
+70/3 or -70/3?
oh man.....thanks so much.....i had tried 70/3 but hadn't tried -70/3.....its working!

12. Oh sign errors, you all-too-familiar seductress you!

13. Originally Posted by maddas
Oh sign errors, you all-too-familiar seductress you!
oh yea.....thats me.....lol

anyways here's another one if anyone's up for it.....I'm at a total loss here.

Two people, Jaime and Tyler, are racing each other. Assume that both their accelerations are constant, Jaime covers the last 1/10 of the race in 7 seconds, and Tyler covers the last 1/7 of the race in 10 seconds. Who wins, and by how much?