# Homework Help: Tricky Kinematics Problems - Desperately need help!

1. Oct 14, 2008

### RPierre

1. The problem statement, all variables and given/known data
I am new to this board, but I am at my wits end trying to solve this problem. If anyone could provide a somewhat detailed solution i would forever be in debt, thanks!

One car, located at position (-29.9 , 0 ) is travelling at 12.7 m/s ( +x)
Another Car, located at position ( 0, -41.0) is travelling at 6.5 m/s ( +y)

+y Direction
^
|
|
----------> + x direction

Calculate the smallest distance between the two cars

2. Relevant equations

I created two functions :
p1 (t) = 12.7t - 29.9
p2 (t) = 6.5t - 41.0

Which represent the position of the cars, based on time, relative to the origin

3. The attempt at a solution

Using pythagorean theorom, i concluded the distance between them can be summarized as

d^2 = (p1(t))^2 + (p2(t))^2

Then i Attempt to solve the minumum of this function, which is where i always screw up.

The correct answer to the problem is 22.9 m
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Oct 14, 2008

### tiny-tim

Welcome to PF!

Hi RPierre! Welcome to PF!
Well, that's fine so far.

Show us how you tried to solve it, and then we'll be able to see where the problem is.