I have question about text .

Hi ,

I have unseen and I don't understand the answer of the teacher in page 5 question 8 (b)

I don't understand it . I "justifctied my answer ":

now it is swinging in the other direction again.

here is the unseen:

http://fgcl16.s1.gns.co.il/ans_G_summ_2009.pdf

Thanks .