Name
Li Mei
Age
13
Study at
No. 1 Middle School, Class 8, Grade 7
School
not very big, trees, flowers
a school library, a reading room……
Teachers
kind ……
After-school activities
play tennis, swim……
My school
The students four groups to discuss the topic.
学生在做模拟"蹦极"的小实验(如图所示).一根橡皮筋一端系一个小石块,另一端固定学生在做模拟实验蹦极.一根橡皮筋一端系一个小石头,另一端固定在点a,b点是橡皮筋不系小石块自然下垂时下端所在的位置,c点是小石块从a点自由下落所能到达的最低点,在小石块从a点到c点的运动的过程,以下说法正确的是（ ）
