STRETCH

Excerpted from Thinking Physics by Lewis Caroll Epstein
Insight Press, 614 Vermont St., San Francisco, CA 94107-2636
www.appliedthought.com/InsightPress
Used with Permission

What does the scale read?

a)   0 lb

b)  10 lb

c)   20 lb

OK, I've tried very hard to solve this. Now, show me the answer.