It's all Newtonian
I experienced an encounter with a galley cart a decade or two back. I was upgraded to first and seated in an aisle seat - 1E IIRC - during a night TO. Since 1F was empty, I was leaning to my right to watch the scenery.
My enjoyment was interrupted by a loud crash just before Vr. A galley cart had come unmoored and, obeying Newton's First Law, tried to stay put while the airplane accelerated around it. It rolled right down the aisle until it bashed against my armrest, delivering its contents on my seat. If I had been sitting upright like a good boy, I might have a broken left kneecap.
Had this event occurred during climb, exactly the same outcome would result; but the cause would be different. The airplane would no longer be accelerating, but the cart would be accelerated by gravity.