you lift a 10 N physics book up in the air a distance of 1m at a constant velocity of .5m/s. What is the work done by the weight of the book?
a) +10 J
b)-10 J
c) +5 J
d)-5 J
10 N is the force of gravity and to find work you do this: W=F_g(change in distance)
(10N)(1m)= +10J so the correct answer is a). Is this correct?
You are doing work on gravity, so it will be negative work done by the book (the book gains energy)
work= weight(height)
-10 J is the work done by gravity.