Chapter 8 - Potential Energy and Conservation of Energy - Problems and Conceptual Exercises - Page 245: 9

$w=540N$

The diver originally has gravitational potential energy. $$U=mgh$$ Solving for the mass yields $$m=\frac{U}{gh}$$ Substituting known values of $U=25000J$, $g=9.8m/s^2$, and $h=46m$ yields a mass of $$m=\frac{25000J}{(9.8m/s^2)(46m)}=55kg$$ To find the weight in newtons, remember that $w=mg$. This yields $$w=(55kg)(9.8m/s^2)=540N$$