Today we 1 only three lessons in the morning. The first lesson is math. It 2 at eight o’clock and finishes at 3 to nine. It is in Room 101. But I don’t like math. Then the second lesson is my favorite 4 —music. It starts at nine o'clock. The 5 lesson in the morning is PE. It starts at ten 6 ten and finishes at five to eleven. We have our lunch at eleven thirty 7 the second floor of dining hall. We have two lessons 8 lunch. Art starts at two and at three o'clock we have a 9 lesson. We can learn a lot of knowledge about China. At about four in the afternoon 10 is over.

300年前，意大利科学家做了这样一个实验：在房间里挂了许多铃铛，然后让蝙蝠在房间中自由飞。第一次未对蝙蝠有任何限制，铃铛未响；第二次蒙住
蝙蝠的眼睛，铃铛也未响；第三次塞住蝙蝠的耳朵，房间中的铃铛响了。下列问题不是该实验所研究的是

小明用如图所示的健身装置来锻炼腿部和手臂的肌肉．使用时，当绳A端固定不动，手在B端用力F_B拉绳，使总重为G的物体匀速上升，若每个滑轮重$\frac{G}{20}$，则F_B=　 ____　；当绳B端固定不动，腿在A端用力F_A拉绳，仍使该重物匀速上升，则F_A= ____　．（不考虑绳重和摩擦）