Answer
$$W = 48,000{\text{ ft - lb}}$$
Work Step by Step
$$\eqalign{
& {\text{From the information we have:}} \cr
& F = {\text{1200 - pound, }}\left( {{\text{force}}} \right) \cr
& D = {\text{40feet }}\left( {{\text{distance}}} \right) \cr
& {\text{Using the Definition of Work Done by a Constant Force}} \cr
& W = FD{\text{, Work}} = \left( {{\text{force}}} \right)\left( {{\text{distance}}} \right) \cr
& {\text{Substituting the known values}} \cr
& W = \left( {{\text{1200}}} \right)\left( {{\text{40}}} \right) \cr
& W = 48,000{\text{ ft - lb}} \cr} $$
