Verified answer

E = mgh

Convert km to m therefore multiply by 1000 = 40 000 m

E = (500 kg)(9. N/kg)(40 000 m)

E = 196 MJ

1) Potential energy is U=mgh

2) Convert 40km to .04m

3)Plug in values into equation

U=(500)(9.8)(.04)

U=196J