在做“探究求合力的方法”的实验中,在水平放置的木板上垫一张白纸,把橡皮条的一端固定在A点上,另一端连接两根细线,然后通过细线用两个互成角度的弹簧测力计来拉橡皮条,使橡皮条与细线的结点伸长到某一点O,此时需记录下:
(1)________________________________________________________________________;
(2)________________________________________________________________________;
(3)________________________________________________________________________;
然后改用一个弹簧测力计把橡皮条拉到O点后再记录下:
(4)________________________________________________________________________;
(5)________________________________________________________________________.