1 Q need help

lundi 31 mars 2014

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





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