# What is the work done?

A painter uses 1.93kJ of mechanical energy to pull on the rope and lift a 20kg paint barrel at constant speed to a height of 7.5m above the ground. How much work was done lifting the paint barrel?

I know that work input is 1.93kJ and the gravitational potential energy (output) is 1470J, but which is the work done?

• Welcome to physics.StackExchange! Please read the rules: meta.physics.stackexchange.com/questions/714/… on posting homework-like questions. You should show the work that you have tried and then pose the question with what concept you are struggling with. – John M Jul 23 '15 at 3:45
• @JohnM: I believe showing the calculation of the PE change in the barrel is enough to satisfy this. OP has isolated the question to which value is being asked for. – Ross Millikan Jul 23 '15 at 4:20
• I'm with Ross, I think this is a fine if not exciting homework question. A problem understanding which value of work represents work done qualifies as a conceptual question. – David Z Jul 23 '15 at 6:31

The work done by the painter is $1.93$ kJ, which represents the force he applied to the rope times the length of the pull. The work applied to the barrel is $1.47$ kJ. The rest went into friction. I believe the question is ambiguous between the two values, but that is an English question, not a physics one.