Physics
posted by Andy .
elbow raises a 1200 N piano a distance of 5 meters using a set of pulleys. elbow pulls in 20.0 meter of rope while exerting a force of 340 N.
a) what is the work output?
b) what is work input
c) what is the mechanical advantage of this machine?
d) what is the efficiency of this machine?

work output=1200*5
work input=20*340
MA=1200/340