This is the 5609th most frequent Japanese word.
ころがっ
"ころがっ" is a conjugated form of the verb "転がる" (ころがる), meaning "to roll" or "to tumble."
The word 'ころがっ' here signifies the action of rolling something, specifically the ball in this case, in a playful context.
こどもがボールをころがして遊んでいます。
The child is playing by rolling the ball.
In this sentence, 'ころがっ' is used to describe the natural motion of a stone rolling down a slope, showcasing an incidental rolling movement.
石が山の坂道をころがっていきました。
The stone rolled down the mountain slope.
Here, 'ころがっ' describes the subsequent action of the cup moving across the floor after being dropped, emphasizing the rolling effect post-impact.