One of the particles is released. Describe the motion of the free particle and calculate the total work done.[/quote]

so;

We know that as increases decreases so,

>

We shall assume it is that is released and is held by an imaginary force.

When is released a force of is pushing it in the positive direction.

After a tiny bit of time, , the particle will have moved and so the force will have decreased meaning that the acceleration of the particle will have decreased...

This is where I get stuck.

how can we express the particles motion if it has no set mass...?

I was thinking change in momentum, but that still depends on mass...

This is an interesting one!

Please can you give me a pointer or two?

Is it actually possible to work it out without mass???