An object is moving at 25 m/s and has a kinetic energy of 12,500 J. If the acceleration due to gravity on Mercury is about 3.8 m/s2 , what would be the weight of this object on Mercury?

(1/2) m v^2 you know is 12500 when v^2 = 625

so calculate m

weight = m g = 3.8 (m) Newtons