Finding the Path of a Particle with Initial Velocity and Force

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Discussion Overview

The discussion revolves around determining the path of a particle given its initial velocity vector and a constant force vector. Participants explore various scenarios that could lead to different types of motion, including parabolic, circular, and straight-line paths. The scope includes theoretical considerations and kinematic equations relevant to motion in physics.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants inquire about how to determine if the path will be parabolic, circular, or straight based on the relationship between the initial velocity vector and the constant force vector.
  • One participant suggests that a parabolic path occurs when the initial velocity vector is neither parallel nor antiparallel to the force vector in a specific frame of reference.
  • Another participant argues that circular motion is impossible if the force vector is constant in the same frame, but proposes a condition involving the magnitude of the force and its projection along the normal to the velocity vector for circular motion to occur.
  • It is noted that a straight-line path occurs when the force vector is parallel or antiparallel to the initial velocity vector.
  • Participants discuss the use of kinematic equations to describe the motion, but there is uncertainty about how to apply these equations to specific scenarios without concrete examples.

Areas of Agreement / Disagreement

Participants express differing views on the conditions necessary for each type of path, indicating that multiple competing models remain. The discussion does not reach a consensus on the best approach to determine the paths.

Contextual Notes

The discussion lacks specific examples or detailed mathematical derivations, which may limit the clarity of the proposed conditions for each type of motion. There are also unresolved assumptions regarding the frames of reference and the nature of the forces involved.

LoveBoy
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Hi There.
I want to ask a question, here it is :-

How to find the path of a particle if initial velocity(vector) is given and constant force(vector) acts on the particle.

Like :-
1) How can we determine the path will be PARABOLIC
2) How can we determine the path will be CIRCULAR.
3) How can we determine the path will be STRAIGHT LINE.If you don't understand , i'll post the question if necessary.
 
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LoveBoy said:
Hi There.
I want to ask a question, here it is :-

How to find the path of a particle if initial velocity(vector) is given and constant force(vector) acts on the particle.

Like :-
1) How can we determine the path will be PARABOLIC
2) How can we determine the path will be CIRCULAR.
3) How can we determine the path will be STRAIGHT LINE.If you don't understand , i'll post the question if necessary.

If you want help with a specific problem, you should post it in the homework section.

In general, you determine the path of a particle by solving the equation(s) of motion.
 
PeroK said:
In general, you determine the path of a particle by solving the equation(s) of motion.
That is my question ?
How do we solve it if initial velocity vector is given and constant force(vector) is given ?
 
LoveBoy said:
That is my question ?
How do we solve it if initial velocity vector is given and constant force(vector) is given ?

You use one of the kinematical equations!

If this is from a school work, you should already know about these kinematical equations. In any case, this is too vague. Pick a specific problem you are having trouble with, attempt as much as you can, and then post in the HW forum. Otherwise, you'll get vague answers to accompany your vague questions.

Zz.
 
LoveBoy said:
That is my question ?
How do we solve it if initial velocity vector is given and constant force(vector) is given ?

You have one vector equation, which is equivalent to three equations, one for each spatial dimension:

##\vec{r} = \vec{r}_0 + \vec{v}_0 t + \frac{1}{2} \vec{a} t^2##

Or:

##x = x_0 + v_{0x} + \frac{1}{2}a_xt^2, \ \ y = y_0 + v_{0y} + \frac{1}{2} a_yt^2, \ \ z = z_0 + v_{0z} + \frac{1}{2} a_zt^2##

Finding the shape of the path then depends on finding a relationship between ##x, y## and ##z##.

You should try some examples in two dimensions.
 
Thanks for posting.
But i don't understand it well.

I'll post a question in HW section .
Thanks again !
 
init velocity vector = P const force vector = Q
LoveBoy said:
1) How can we determine the path will be PARABOLIC
if in frame A ,P is non parallel and non antiparallel to Q -- parabolic path in frame A
LoveBoy said:
2) How can we determine the path will be CIRCULAR
if Q is const in frame A, then circular motion impossible in frame A
if only mag of Q const , then ---
if (|P|^2) / (proj of instantaneous Q vector along normal to P) = const ---- circular motion
LoveBoy said:
3) How can we determine the path will be STRAIGHT LINE.
Q parallel or anti parallel to P --straight line
 

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