A tool or machine's work efficiency is represented by the ratio of the amount of energy exerted and the amount of work done by the object. Thus, if you exert 1500 J work and the hammer does 825 J, the work efficiency is
[tex] Efficiency = \frac{825}{1500} = 0.55 [/tex]
[tex] Efficiency = 55% [/tex]
Thus, the efficiency of the hammer is 55%.
Answer: 55%