Finding Distance b/w Point A and B with Kinematic Formulas

  • Thread starter Thread starter lektor
  • Start date Start date
  • Tags Tags
    Mechanics
Click For Summary

Homework Help Overview

The problem involves two cars moving toward each other along a straight road, with specified speeds and accelerations. The objective is to determine the distance between the starting points of the two cars, A and B, based on their motion characteristics and the time interval between their two meetings.

Discussion Character

  • Exploratory, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to derive a formula using kinematic equations but expresses uncertainty about their approach. Some participants question the consistency of units in the original poster's result and suggest alternative formulas. Others propose expressing the positions of both vehicles in terms of time to derive a quadratic equation.

Discussion Status

The discussion is active, with participants providing different formulas and questioning the validity of the original poster's approach. There is a mix of interpretations and suggestions, but no consensus has been reached regarding the correct method or formula.

Contextual Notes

Participants are navigating issues related to unit consistency and the formulation of equations based on the cars' motion characteristics. The original poster also notes a lack of familiarity with math notation, which may affect the clarity of their expressions.

lektor
Messages
56
Reaction score
0
This question is just a practice for creating equations for suiting situations but i feel as if I've taken the completely wrong appoach..


Two cars begin to move toward each other simultaneously along a straight road. Car 1 starts from point A at a speed of V1; Car 2 starts at point B at a speed V2.The acceleration of car 1 is a1; it is directed toward A,
The acceleration of car 2 is a2; it is directed toward B. In the process of motion, the cars meet twice; the time interval between the meetings is t. Find the distance between A and B.

Some help would be great, so far my approach was using kinematic formulas.

I finished with [tex]D = \sqrt{\frac{Vi1*T*a1*T^2}{Vi2*T*a2*T} }[/tex]

Sorry about the mathlatex in currently reading the guide.
 
Last edited:
Physics news on Phys.org
The units in your result don't agree. They are ms, and not m.

I came up with this formula:


[tex]D = \frac{(v_{01} + v_{02})^2 - (\frac{a_1 + a_2}{2\Delta t})^2}{2(a_1 + a_2)}[/tex]
 
ramollari said:
The units in your result don't agree. They are ms, and not m.

I came up with this formula:


[tex]D = \frac{(v_{01} + v_{02})^2 - (\frac{a_1 + a_2}{2\Delta t})^2}{2(a_1 + a_2)}[/tex]

Your Answer looks quite well thought out, could you please give some explanations of how you reached it :)?
 
Express the positions x of both vehicles in terms of time. Equalize them, and you get a quadratic equation for time, that of course gives two results. Then, the procedure is simple:

[tex]\Delta t = \frac{\sqrt{\Delta}}{a}[/tex]

Both Delta and a will contain the quantities D, a1, a2, v01, v02. So, solve for D to arrive at that result.
 

Similar threads

  • · Replies 30 ·
2
Replies
30
Views
3K
Replies
1
Views
3K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 26 ·
Replies
26
Views
4K
  • · Replies 9 ·
Replies
9
Views
4K
Replies
14
Views
3K
  • · Replies 12 ·
Replies
12
Views
2K
  • · Replies 12 ·
Replies
12
Views
3K
Replies
4
Views
3K
  • · Replies 5 ·
Replies
5
Views
8K