A crane does 62,500 joules of work to lift a boulder a distance of 25.0 meters. How much did the boulder 
weigh?

[tex]W=Fs \\ F=\frac{W}{s}[/tex]W - workF - weights - distance[tex]W=62 500 \ J = 62 500 \ N \cdot m \\
s=25 \ m \\ \\
F=\frac{62500 \ N \cdot m}{25 \ m}=2500 \ N[/tex]The boulder weighed 2500 newtons.