Relating Kinetic Energies and Masses of Two Objects

[B3NR4Y]

Homework Statement

Two objects of inertias m₁ and m₂ start from rest and then interact with each other (assume neither is interacting with any other object).
What is the ratio of their kinetic energies at any instant?

Homework Equations

[itex] \frac{K_{1}}{K_{2}} = ? [/itex]
The first part of the equation asked me to relate velocities to masses and I got a correct answer of

[itex]\frac{v_{2x}}{v_{1x}} = -\frac{m_{1}}{m_{2}} [/itex]

The Attempt at a Solution

I know that Kinetic Energy is half of the mass times the square of the velocity, and that's where my attempt falls apart, because I have to express the answer in terms of m₁ and m₂, but they're already in KE so I don't understand how that works out. My answer I got was

[itex]\frac{K_{1}}{K_{2}} = \frac{m_{2}}{m_{1}} [/itex]

Without the negative cause it is the square of the velocity and that will eliminate any negatives. Please help.

 

[nasu]

So what is your question?
The answer looks OK.

 

[B3NR4Y]

So what is your question?
The answer looks OK.

It's not okay though :( apparently I am not correct

 

[Vibhor]

The answer you have obtained is correct .

 

[nasu]

It's not okay though :( apparently I am not correct

How do you know this? What do you think is the correct answer?

 

[B3NR4Y]

How do you know this? What do you think is the correct answer?

It's part of a homework assignment and when I put in an answer it spits out a correct or incorrect judgement. I put in my answer and it's incorrect. The professor said things like this would happen though, and when they did to come to him because we're using a new system and there are mistakes in it that he's found. I hope that is the case because I tried every combination of subscript and now they most I can get on the question is 50% for a correct answer regardless of the amount of tries.