The gravitational potential energy referred to the ground level is given by
[tex]U=mgh[/tex]
where m is the mass of the object, [tex]g=9.81 m/s^2[/tex] is the gravitational acceleration and h is the height of the object with respect to the ground.
Therefore in our problem the potential energy is
[tex]U=(150 kg)(9.81 m/s^2)(5 m)=7357.5 J[/tex]
