What could be causing the discrepancy in Y0 when finding the placement vector?

  • Thread starter Thread starter devanlevin
  • Start date Start date
  • Tags Tags
    Idea No idea
Click For Summary

Homework Help Overview

The discussion revolves around the calculation of velocity and placement vectors based on given acceleration functions. The original poster is attempting to find the placement vector after integrating the acceleration components, starting from an initial position and velocity.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • The original poster integrates the acceleration functions to find velocity and placement vectors but encounters a discrepancy in the Y0 value. Participants discuss the necessity of including a constant of integration and question the role of initial conditions in determining this constant.

Discussion Status

Participants are exploring the implications of the constants of integration in the context of the problem. Some guidance has been offered regarding the need to adjust the constant to ensure that the initial conditions are satisfied, particularly for the Y component.

Contextual Notes

The discussion highlights the importance of correctly applying initial conditions and constants of integration when integrating functions in physics problems. The original poster expresses frustration over the discrepancy despite repeated checks of their work.

devanlevin
given the acceleration
Ax=6t^2
Ay=-0.66PI*cos(0.66PI*t)
and knowing that the starting point was (0,0) and that the starting velocity was V0=(-1,0)
find the Velocity vector and the placement vector
si what i did was- 1st integral on Ax Ay getting
Vx= 2t^3-1
Vy=-sin(0.666PI*t)

which is fine and is true to the facts- V0=(-1,0)
but then, 2nd intergal, integral in Vx, Vy
and
Rx= 0.5t^4-t
which is fine, X0=0
BUT
Ry= 1.5PI*cos(0.66PI*t)
and then Y0 is not 0, i have checked and double checked and triple checked and cannot find my fault, any ideas?/
 
Physics news on Phys.org
devanlevin said:
Ay=-0.66PI*cos(0.66PI*t)
and knowing that the starting point was (0,0) and that the starting velocity was V0=(-1,0)
…
Vy=-sin(0.666PI*t)
…
Ry= 1.5PI*cos(0.66PI*t)
and then Y0 is not 0, i have checked and double checked and triple checked and cannot find my fault, any ideas?/

Hi devanlevin! :smile:

Whenever you integrate, you must include a constant of integration.

That constant just happened to be 0 in the other parts of the question …

but it isn't zero here … that's all! :wink:
 
but i did, added Vx0=-1 and Vy0=0, and isn't the constant in this case X0 and Y0, which are both 0 anyway??
 
Hi devanlevin! :smile:
devanlevin said:
but i did, added Vx0=-1 and Vy0=0, and isn't the constant in this case X0 and Y0, which are both 0 anyway??

ah, I see now …

No, X0 and Y0 are the "target figures", not the constants themselves.

You have to choose a constant so that Y(0) = Y0 …

in other words, choose C so that 1.5*π*cos(0.66πt) + C = 0. :smile:
 
thanks
 

Similar threads

Projectile Motion: Dropping a Package
  • · Replies 6 ·
Replies
6
Views
5K
What is the height of the cliff?
  • · Replies 1 ·
Replies
1
Views
5K
Integration, where am i going wrong here?
  • · Replies 4 ·
Replies
4
Views
2K
Angular momentum problem starting from some point on the x-axis.
  • · Replies 3 ·
Replies
3
Views
2K
Find the scalar, vector, and parametric equations of a plane
  • · Replies 10 ·
Replies
10
Views
3K
Comp Sci Efficient Fortran Method for Trajectory Plotting with 4d Vector-First Order ODE
  • · Replies 18 ·
Replies
18
Views
3K
Finding voltage due to spherical charge
  • · Replies 23 ·
Replies
23
Views
4K
What could be causing my rocket to never land on the moon?
  • · Replies 6 ·
Replies
6
Views
3K