# Homework Help: Kinematics-Motion in one dimension

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1. Jun 10, 2016

### Googlu02

1. The problem statement, all variables and given/known data
Two points P and Q move in a straight line AB.The point P starts from A in the direction AB with velocity and acceleration [PLAIN]http://latex.artofproblemsolving.com/b/b/2/bb2c93730dbb48558bb3c4738c956c4e8f816437.png.At [Broken] the same instant of time Q starts from B in the direction of A, with a velocity http://latex.artofproblemsolving.com/0/5/5/0559ffc8c62a08ff533f3fcd1a5c1713a520755d.png and acceleration [PLAIN]http://latex.artofproblemsolving.com/3/7/a/37a9e7fca70e2dce829d902af2088735306bc1a3.png.If [Broken] they pass each other at the middle point of AB and arrive at the other end of AB with equal velocities, then prove that

2. Relevant equations
Let be the distance AB, be the time it takes to get midway.

Then, [PLAIN]http://latex.artofproblemsolving.com/b/2/c/b2c07b1586491a4fe17cfa89fa189a2ae96b7aa0.png. [Broken]

We also have [PLAIN]http://latex.artofproblemsolving.com/0/0/a/00a11d7cdd2ce508b54ea4592c254b2a6a2abc72.png.[/B] [Broken]

3. The attempt at a solution
I tried to do the problem by the above method but I am not getting the desired result despite many algebraic manipulations.Please can someone help me with this proof.

Last edited by a moderator: May 7, 2017
2. Jun 10, 2016

### Staff: Mentor

Hi Googlu02, Welcome to Physics Forums.

Consider finding separate expressions for L using both starting formulas. For the first starting point, keep in mind that L = L/2 + L/2, and that you can eliminate t1 from the result knowing that L/2 = L/2.

Show the details of what you try.

3. Jun 10, 2016

### Ray Vickson

Please avoid using bold fonts; it looks like you are yelling at us.

Last edited by a moderator: May 7, 2017
4. Jun 10, 2016

### Googlu02

Sorry for using bold font.

5. Jun 10, 2016

### Googlu02

Yes thank you , I got the solution.Here it is as follows:
From the first equation we get $$t_1=\frac{2u_1-2u}{f-f_1}$$
Now substituting the value of L in the second equation we get the desired result..