**1. The problem statement, all variables and given/known data**

a stone is thrown vertically downward from the top of 40 m tall building with an initial speed of 1 after 2s the stone will have traveled a distance of?

**2. Relevant equations**

x=vt+0.5at^2

vf=vi+at

**3. The attempt at a solution**

1(2)+0.5(-9.8)(2)^2=-17.6

the answer i was given is 22

and i tried to put 9.8 without negative and it was 21.6 is this one right ??

why is the acceleration positive while going up is negative ???

waiting and thank you

http://ift.tt/1jQ13iD