"Behavior" word in the title is not very correct.
I'm in a train at a railway station and on the platform there is a glass case (the mass of case is 5 kg and if it gets hit with a velocity of 10 N then the glass will break), a frame of reference is attached to me. Now my train starts with an acceleration of $2\, m/s^2$. Now according to me I'm at rest and glass case is moving backward and so the acceleration on the glass case is $2\, m/s^2$ (at present I'm not considering the direction). Therefore the force acting on the glass case is $F=ma=5\times 2=10\, N$ at this the glass case should break, but this is not happening. Whereas according to a frame of reference attached to a person on the platform every thing is fine(i.e. there is no force(horizontal) acting on the glass case).
The law cannot be wrong and so that means that I'm somewhere wrong. I cannot find my mistake so please help me.