S1 문장의 [______]에 들어갈 단어는?

난이도 고난도 · 힌트를 덜 열수록 높은 점수 (현재 5점)
To determine the [______] of my bowling ball, I might put it onto a balance and compare it with a known mass, such as a number of metal cubes each weighing 1, 10, or 100 grams.